Proceedings Contents WATER CONFERENCE - 2013 n Preface MANAGEMENT OF WATER RESOURCES IN NORTH EAST n Foreword 1. Sizing of Kulsi Reservoir System Using Non-Linear Optimization and Simulation REGION WITH SPECIAL REFERENCE TO FLOOD AND Dr. Bibhash Sarma, Krishna Kamal Das, N.N. Patwari 1 EROSION MANAGEMENT 2. Land & Water Management in the Flood Affected Areas of Assam: A Case Study in Dharmtul — Nelli Area under , Assam Jiten Malakar 14 3. Management of Water Resources of the North East Region with Special Reference to Assam Er. Ramesh Ch. Borah 30 4. River Bank Erosion Management in Assam Sri Uma Baruah, Dr. Rajib Kumar Goswami 41 5. GEO Tube Embankments-Challenges Before the Engineers-A Case Study Er. Nayanjyoti Goswami 57 Proceedings of the 6. Operational Flood Early Warning System (FLEWS) - A geospatial and hydro-met approach as developed by NESAC for Government of Assam Assam Water Conference - 2013 Diganta Barman, S.S Kundu, Jonali Goswami, Ranjit Das, NGR Singh, Arup Borgohain, 21-22 February, 2013 Rekha Bharali Gogoi, Victor Saikhom, Suranjana B Bora, S. Sudhakar 61 7. The Study of Water Uses Based on Water Quality of the River Brahmaputra, Assam Dhwajendra Nath Das 67 8. Infiltration Studies in Kulsi Pilot Basin (Assam/) Under Different Landuse and Soil Types for Efficient Management of Groundwater for Irrigation Purpose S.R. Kumar, S. Chakma 78 9. Water Quality Indices to Ensure the Suitability of Groundwater for Irrigation S.R. Kumar 85 Editors Haren Kakati 10. Hydro Electric Power Generation in Irrigation Canals Kamal Ch. Saikia 93 Pradipta Pran Changkakati 11. Some Aspects of the Institutional Strengthening Component : AIFRERMIP Ranjit Galappatti 102 12. Model Deflector as Safety Measure to Embankment system of Flashy River Er. Utpal Majumdar 110 13. Basin level integrated water resources management (IWRM) and eco-system management-A strategy to respond to climate change S. C. Patra 120 Organised by 14. A Study on the Change Detection of Land Use/Land Cover of the Island of Assam Water Resources Department Swapnali Barman, M.K.Dutta, S.P. Aggarwal 129 Government of Assam 15. Brahmaputra Basin: Some thoughts on Development and Management of its Water Resource Dispur, Guwahati-781006 Chandan Mahanta 139 16. Need of Integrated Approach for Mitigating Flood and Erosion Problem of Assam Arup Kumar Sarma 152 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

unique set of physical conditions to which it must conform, hence standard design leading to simple solutions applicable to all the projects are rarely available. The special conditions of Sizing ofulsi K Reservoir System Using each project must be met through an integrated application of the fundamental knowledge of the various disciplines. One of the areas of civil engineering which really pioneered the use of optimization techniques Non-Linear Optimization and Simulation in water resources systems planning, design, operation and management. Optimization tools Dr. Bibhash Sarma are utilized to facilitate optimal decision making in the planning, design and operation of especially Associate Professor large scale water resources systems. The use of optimization tools as the most important Assam Engineering College component of Decision Support Systems are not confined only to the quantity aspect of water. Designing of optimal strategies for reservoir releases for water quality augmentation, or Krishna Kamal Das N.N. Patwari maximizing hydropower generation, irrigation, water supply etc. are only a few examples of Lecturer, Bongaigaon Polytechnic Professor, Assam Engineering College using optimization tools for evolving economically efficient management strategies. Application of optimization techniques are most exciting, challenging and truly large scale ABSTRACT when it comes to the management of water resources systems both in terms of quality and Water has great contribution towards the development of human civilization. Rapid quantity. The economics involved with large scale water resources projects are indeed very development in human civilization raises the need for the immediate development of water complex as it influences the life and future of many sections of the society and different resources. The application of optimization techniques to reservoir operation has become a geographical regions in different ways. major focus of water resources planning and management. Water use involves a large number In real life, most of the water resources optimization problems involve con?icting objectives, of stakeholders with different objectives, and optimization techniques are expected to provide for which there is no efficient method for ?nding multiple trade-off optimal solutions. Most of the balanced solutions between often conflicting objectives. The paper proposes an avenue for reservoir systems serve multiple purposes and they are multi-objective in nature. To optimize changing traditional reservoir operation into optimized strategies, taking advantage of the such a complex reservoir system, the dynamic programming (DP), linear programming (LP) rapid development in computational techniques. The main contribution of the paper is the and non-linear programming (NLP) have been widely applied in the past (Yeh, 1985). development of a framework in which a simulation model is coupled with non linear optimization technique using MS Excel solver which is easily available and can be easily utilized by field Hydropower generation is one of the vital components of reservoir operation, especially for a large multi-purpose reservoir. Deriving optimal operational rules for such a large multi- engineers for reservoir planning in their practical field. Ecological, irrigation and hydropower purpose reservoir serving various purposes like irrigation, hydropower and flood control are demands are considered in this model. complex, because of the large dimension of the problem and the complexity is more if the Key words: Non-Linear Programming, Simulation, Reliability, Reservoir Planning hydropower production is not an incidental. Thus optimizing the operations of a reservoir 1. Introduction serving various purposes requires a systematic study. In a recent study, such a large multi- purpose reservoir, namely, Koyna reservoir operations (R.Arunkumar, V.Jothiprakash, 2012) Water is the most essential substance for survival of life on the earth. As demand for water are optimized for maximizing the hydropower production subject to the condition of satisfying is increasing day by day due to the increase in population, the engineers and planners have the irrigation demands using a non-linear programming model. The hydropower production been compelled to plan in more comprehensive and ambitious way to meet up the demand. from the reservoir is analyzed for three different dependable inflow conditions, representing Water has contributed greatly towards development of human civilization. Rapid development wet, normal and dry years. For each dependable inflow conditions, various scenarios have in human civilization raises the need for the immediate development of water resources. The been analyzed based on the constraints on the releases and the results are compared. The conservation and efficient use of water are the main elements in the planning. In India, the annual power production, combined monthly power production from all the powerhouses, rainfall normally comes during monsoon season and is unevenly distributed over space and end of month storage levels, evaporation losses and surplus are discussed. From different time. So it is very important to utilize the limited water resources in an efficient & sustainable scenarios, it is observed that more hydropower can be generated for various dependable manner. inflow conditions, if the restrictions on releases are slightly relaxed. The development of water resources involves the conception, planning, design, construction Aiming at the problem that traditional optimal operation of hydropower reservoir pays little and operation of facilities to control and utilize water. Water resources problems are attention to ecology, an optimal operation model of multi-objective hydropower reservoir with interdisciplinary in nature. Further each water resources development project encounter a ecology consideration is established which combines the ecology and power generation

1 2 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

(Xuewen Wu et al, 2011). The model takes the maximum annual power generation benefit, flow; quadratic programming; dynamic programming (DP); nonlinear programming (NLP); the maximum output of the minimal output stage in the year and the minimum shortage of mixed integer linear programming (MILP); interior point method; and simulation. During the ecological water demand as objectives, and water quantity balance of reservoir, reservoir past decade, major advances in the development of software tools (solvers) are witnessed storage, discharge flow, output and so on as constraints. for solving large-scale linear and nonlinear optimization problems. Most of the solvers are Optimization methods have been proved of much importance when used with simulation available commercially and are user friendly. Accompanied by the drastic increase in modeling and the two approaches when combined give the best results. (Deepti Rani et.al, computational power it is now possible to solve large-scale optimization problems on a desktop 2010) PC within reasonable execution time. 2. The Problem A real-time operational methodology has been developed for multipurpose reservoir operation for irrigation and hydropower generation with application to the Bhadra reservoir system (S. Practicing engineers always find it difficult to use system analysis techniques to optimize Vedula & S. Mohan,1990) in the state of Karnataka, India. The methodology consists of three water resources projects due to complicated procedures and involvement of costly softwares. phases of computer modeling. In the first phase, the optimal release policy for a given initial They frequently rely only on simulation process. But, simulation cannot guarantee global storage and inflow is determined using a stochastic dynamic programming (SDP) model. Stream optimization, it gives local optima only. In this work, how optimization technique can be used flow forecasting using an adaptive Auto Regressive Integrated Moving Average (ARIMA) model using easily available Microsoft Office Excel in Solver platform is exhibited for optimizing constitutes the second phase. A real-time simulation model is developed in the third phase reservoir system. A proposed multi-purpose reservoir in Kulsi river in Khasi Hills of Meghalaya using the forecast inflows of phase 2 and the operating policy of phase 1. is selected to demonstrate the procedures. The reservoir serves hydropower generation and irrigation. Here, a combined Non-Linear Programming (NLP) and simulation model is used Despite the fact that most integrated use management problems are nonlinear in nature, to study the required reservoir capacity, firm power potential and irrigation potential under the application of nonlinear programming (NLP) has been rather limited. This may be because of given limitations of inflow discharge and topography. the complexity and the slow rate of convergence of the NLP algorithms, difficulty in considering stochasticity and possibility of getting a local instead of global optimal solution (Yeh, 1992). 3. Study Area: Kulsi Basin Genetic algorithm (GA) is a search procedure which combines an artificial survival of the The river Kulsi, is a south bank tributary of the river Brahmaputra. It is known as Khri in the fittest with genetic operators abstracted from nature, used successfully in optimization of upper catchments in Meghalaya. The river originates from the northern slopes of the Khasi water systems (Wang, 1991; Ritzel el at, 1994; Mckinney and Lin 1994; Aly and Peralta, hill ranges. It enters Assam at Ukium and after flowing through the plains of 1999; Patrick Reed and David E Goldberg 2000). of Assam, outflows into the Brahmaputra near Nagarbera. The river has a total catchments of 3231 sq. km. Out of which about 1666 sq. km is in Khasi hills in Meghalaya and rest is in the Zambelli, M.S.(2009) proposes an operational policy for long-term hydropower scheduling plains of Assam. The total length of Kulsi from its source to outfall is about 220 km. Out of based on deterministic nonlinear optimization and annual inflow forecasting models using an which 100km is in Meghalaya and rest 120 km is in Assam. A Location map & Satellite map open-loop feedback control framework. of the river Kulsi is shown in Fig-1. Sarma and Srivastava (2005) developed a simulation model to analyze different promising cases of an intra-basin water transfer proposal linking Parbati, Kalisindh and Chambal rivers in Chambal basin (India). The model is applied to a system of five reservoirs, where water is to be transferred from three proposed reservoirs to the two existing reservoirs. The initial estimates for the model is taken from the results of three optimization models, namely, improved general purpose yield model (IGPYM), controlled input model (CIM) and procurement problem model (PPM). System analysis techniques have been used successfully in the management and operation of complex reservoir systems. The complexities of a multipurpose multiple reservoir system generally require release decisions to be made by an optimization or simulation model. The choice of methods depends on the characteristics of the system being considered, on the availability of data, and on the objectives and constraints specified. Most of the optimization models are based on some type of mathematical programming technique. In general, the available methods can be classified as follows (Yeh, 2003): linear programming (LP); network Fig 1: Location Map of Kulsi River 3 4 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Kulsi river is also famous for dolphin, locally known as 'sihu', (Fig. 2). Sharp decline in the 5. Present Status of the Project population of endangered river dolphins, has prompted the Union Ministry of Environment 1. The survey and investigation work of Kulsi multipurpose project was undertaken in and Forests to initiate action to declare Kulsi river, the only known abode of resident river 1997. dolphins in the world, as a wildlife sanctuary for effective conservation of the species. Sources informed that the Union Ministry vide letter No. 6-13-114/2001/RONE/AS/2702-4 asked the 2. A Design team of CWC visited project sites of Kulsi MP Project on 19th and 20th Principal Secretary, Environment and Forests, Government of Assam, to carry out population December, 2009 and suggested some modification in the lay out and some additional estimation of river dolphins in Kulsi river and consider declaring the area a wildlife sanctuary geological investigation. for effective conservation of river dolphins. 3. Hydrological studies have been vetted by CWC. 4. Power Potential Studies including techno-economic analysis on financial soundness of the project as suggested by the Design Team has been carried out and submitted to CEA for concurrence. 5. Topographical survey, Geological investigation and construction materials surveys as suggested are in progress. 6. EIA & EMP studies in final stage. 7. CWC has been requested to take up the work of balance survey and investigation and preparation of DPR so as to complete the DPR within scheduled time of completion. Fig 2: Dolphin in Kulsi River 8. The high-powered steering committee for implementation of national projects has Altogether 28 (best estimate) dolphins (minimum 24 to maximum 30) with an encounter directed to complete the detailed project reports (DPR) for the Kulsi multipurpose rate of 0.37 dolphins per km were recorded in this river. (Courtesy -Dolphin Conservation hydro project in Assam by March 2013. Project, Aaranyak, Guwahati, Assam, India. Dec'2007). 6. Salient features of the Kulsi Dam Project 4. The Project Proposal i) Location of the Dam Project site Lat 25 50 20 N The Kulsi Multipurpose Long 91 2 28 E Project envisages (1.50 km D/S of Ukium village) construction of a dam across ii) Name of river Kulsi the river Kulsi at about 1.5 km iii) Catchments area upto Dam site 1646.69 Sq. km downstream of Ukium village in Assam for hydro power, iv) Dam site distance from NH 37 32 km irrigation and flood v) Average annual discharge 69.73 Cumec moderation. Three saddles vi) Average annual yield at Dam site 2199 Mcm dams at Chikadonga, vii) Average dry period yield 485 Mcm Mejengabari and Doledonga are proposed to be viii) Average Monsoon period yield 1714 Mcm constructed for full utilization ix) 90% dependable yield 1573 Mcm of the potential of the project. x) Average annual silt load 115.27 Ha.m The reservoir so created will xi) Dead storage level (100 years sedimentation) EL 60.75m provide storage for Fig 3: Index map showing dams of Kulsi M.P Project xii) Minimum draw down level EL 80m multipurpose benefit of flood xiii) Deepest bed level 58m control, irrigation and power generation. A map showing the detailed project proposal is shown in Figure 3. It is proposed to locate the spillway at the main dam site at Ukium. Mcm: million cubic metre 5 6 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Table 1 shows some multipurpose projects in North-East India and their status. 7.2 Mean Monthly reservoir Evaporation data: Table 1: Multipurpose projects in North-East India and their status There is no evaporation data at the dam site at present. Evaporation data available at the Lokapriya Gopinath Bordoloi International Airport, Borjhar, Assam, have been considered for Sl No. Name of Project Status (as on 31-03-2012). the project. Figure 5 shows the average evaporation in different months. 1 Siang Dam Project DPR Completed (Handed over to NHPC) 2 Subansiri Dam Project DPR Completed (Handed over to NHPC) 3 Tipaimukh Dam Project DPR Completed (Handed over to NEEPCO) 4 Pagladiya Dam Project Under Brahmaputra Board 5 Bairabi Dam Project DPR Completed (Handed over to Govt. of Mizoram) 6 Debang Dam Project DPR Partially Completed 7 Lohit Dam Project DPR Partially Completed (Project entrusted to Private Developer by Govt. of Arunachal Pradesh) 8 Kynshi Stage-I Dam Project Under Survey & Investigation (Handed over to private developers by Govt. of Meghalaya) 9 Kynshi Stage-II Dam Project Under Survey & Investigation (Handed over to private developers by Govt. of Meghalaya) 10 Kulsi Multi-Purpose Under Survey & Investigation 11 Simsang Dam Project Under Survey & Investigation Fig 5 : Average evaporation Vs month curve 12 Jiadhal Dam Project Under Survey & Investigation 7.3 Reservoir Elevation-Area-Capacity Characteristics 13 Killing Dam Project Under Survey & Investigation The area-capacity-elevation values have been worked out from reservoir area maps 14 Noa-Dehing Dam Project Under Survey & Investigation developed by the project authority. Original area-capacity values have been considered for 7. Input Data the purpose of the present study. Figure 6, Figure 7, and Figure 8 exhibit Storage-Elevation, Storage-Area, and Area -Elevation curve respectively. 7.1 Inflow series at monthly time step: The Hydrology (NE) Directorate of the Central Water Commission recommended a runoff series (1964-2000) for preliminary planning purposes of the Kulsi Multipurpose Project. That series has been extended to 2003 by incorporating additional data and adopted for this study. Presently there is no data collection Fig 4: Av. Inflow Vs month curve Fig 6: Storage Vs Elevation Curve station at the dam site. The average monthly inflows at the dam site are presented in Figure 4. 7 8 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

8 .Non-Linear Programming and Simulation Model Formulation and Application A combined non-linear programming model (NLP) and simulation model is used. In simulation, it is assumed that in any time period if water is available, demand has to be met. Ecological, irrigation and hydropower demands are considered in this model. As per the guidelines provided by National Water Development Agency, Govt. of India, 10% of the average non-monsoon flow is considered as ecological demand; and this amount should be available in the downstream river at any time. As per the National Water Policy in India, the ecological and irrigation demand are given higher priority than the hydropower demand. In Kulsi Project, irrigation and power generation are compatible, i.e., irrigation yields are also available for power generation. The objective function of the NLP is chosen as to minimize the reservoir capacity by Fig 7: Storage Vs Area curve changing the firm power under all the constraints of conventional simulation model and also by maintaining irrigation release at minimum 75% reliability with given demand, and maintaining 90% reliability for firm power generation. Once the required reservoir capacity is obtained, only simulation model is run to assess the behavior of the project with changing scenarios. From the result of the NLP, it was seen that the reliability of irrigation release is very high (95.69 %), which indicates that the annual target irrigation release can be increased. To see, how these incremental increase in annual irrigation release affects the mean annual power generation, simulation model is run and results of each run is recorded. 9. Results After developing the simulation model, the optimum reservoir capacity has been obtained by Non-Linear programming with Microsoft Excel Solver platform. The optimum reservoir capacity has been obtained subject to constraints of irrigation reliability ? 75 % and power reliability ? 90 %. Deterministic inflow, flow continuity, storage bounds, storage-area-elevation Fig 8: Area Vs Elevation Curve relationships, demand requirements, evaporation losses, spills, plant capacity constraints/ 7.4 Irrigation demand relationships are incorporated in to the model. The NLP gave minimum required reservoir capacity as 324.934 Mcm, fixing firm power at 90% reliability as 6.65 MW. The plant capacity Gross command area of Kulsi Project has been estimated to be 37908 Ha. An area of assumed here is 29 MW as it is proposed by the authority. 23882 Ha (Net Irrigable Area) is to be irrigated using the water of Kulsi reservoir. The irrigation demands as assessed by the project authority have been considered for the purpose of the Simulation model is run to see the behaviour of the reservoir project under different present study. Figure 9 shows the monthly irrigation demands. The total annual irrigation scenarios. Table 2, Table 3 and Table 4 show the results. demand is 171.27 Mcm. Table 2: Reservoir capacity Vs irr. rel/pow.rel/av.ann.irr/av.ann.pow Reservoir Irrigation Power Average annual Average annual Capacity (Mcm) reliability (%) reliability (%) irrigation (Mcm) power (firm + secondary) (MW) 300.00 95.28 85.83 170.47 102.68 315.00 95.69 88.09 170.80 105.23 320.00 95.69 89.32 170.80 106.15 321.93 95.69 90.14 170.80 106.58 325.00 95.69 90.55 170.80 107.18 330.00 95.69 90.97 170.80 108.47 350.00 96.10 92.20 171.29 112.15 Fig 9: Monthly irrigation demands Vs month curve

9 10 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Table 3: Firm Power Vs irr. rel/pow.rel/av.ann.irr/av.ann.pow. Firm Power Irrigation Power Average annual Average annual (MW) reliability (%) reliability (%) irrigation (Mcm) power (MW) 7.50 92.40 77.41 167.48 101.42 7.00 94.46 85.01 169.95 104.39 6.50 95.89 91.58 171.01 107.80 6.65 95.69 90.14 170.80 106.58 6.00 96.10 93.43 171.29 110.38 5.50 96.10 94.05 171.29 111.12 5.00 96.10 95.07 171.29 111.73 Though the given annual irrigation demand is 171.27 Mcm, the reliability of irrigation release obtained for this demand is 95.69 %. This reliability is far more than the target reliability of 75%, which shows that the annual irrigation release can be increased. Simulation model is run to see how much the annual irrigation release can be increased without compromising the 90% power reliability and 75% irrigation reliability. Fig 10: Average annual irrigation (Mcm) Vs Average annual power(MW) curve Considering reservoir capacity 321.93 Mcm and firm power 6.65 MW as constant, the 9. Conclusion annual irrigation demand is varied. Table 4 shows the results of the iterations, where annual irrigation demand 204.98 Mcm gives the best reliablity of hydropower and irrigation. The Kulsi multipurpose reservoir is proposed for hydropower generation, irrigation and flood control. Ecological, irrigation and hydropower demands are considered in this study. As Table 4: Annual Irrigation Demand Vs irr. rel/pow.rel/av.ann.irr/av.ann.pow. per the guideline provided by National Water Development Agency, Govt. of India, 10% of Annual Irrigation Irrigation Power Average annual Average annual the average non-monsoon flow is considered as ecological demand; and this amount should Demand (Mcm) reliability (%) reliability (%) irrigation (Mcm) power(MW) be available in the downstream river at any time. A combined non-linear optimization and 171.27 95.69 90.14 170.80 106.58 simulation model is applied. The results show that required minimum Reservoir capacity is 321.93 Mcm, which can produce a firm power of 6.65 MW. The annual irrigation demand can 175.00 95.69 90.14 174.51 106.58 be increased up to 204.98 Mcm without compromising 90% dependable firm power and 75% 200.00 95.69 90.14 199.36 106.59 reliable irrigation release. Average annual irrigation and average annual power at 171.27 204.98 95.69 90.14 204.31 106.58 Mcm annual irrigation demand are170.80 Mcm and 106.58 MW, respectively, whereas, average annual irrigation and average annual power at 204.98 Mcm annual irrigation demand 220.00 95.69 89.94 219.23 106.55 are 204.31 Mcm and 106.58 MW, respectively. Maximum observed spill is 573.269 Mcm. 250.00 94.87 89.73 248.84 106.54 The combined NLP and simulation model adopted here uses Microsoft Excel in Solver platform, Average annual irrigation demand and average annual power have been obtained and can be used by practicing engineers with ease. corresponding to various annual irrigation demands without compromising 90% dependable References firm power. The iteration results are tabulated Table 4 and corresponding curve have been 1. Deepti Rani, Maria Madalena Moreira (2010), "Simulation-Optimization Modeling: A shown in Figure 10. Survey and Potential Application in Reservoir Systems Operation". Water Resources Management,April 2010, Volume 24, Issue 6, pp 1107-1138. 2. R. Arunkumar, V. Jothiprakash (2012), "Optimal Reservoir Operation for Hydropower Generation using Non-linear Programming Model" Journal of The Institution of Engineers (India): Series A, September 2012.

11 12 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

3. Sarma B., and Srivastava D.K. (2005) "Simulation study of a river linking Project." Proc. of the International Conference on Hydrological Perspectives for Sustainable Development (HYPESD-2005), Indian Institute of Technology Roorkee, Feb.23-25, 2005,pp598-608. 4. S. Vedula & S. Mohan (1990), "Real-time multipurpose reservoir operation: a case study", Hydrological Sciences - Journal - des Sciences hydrologiques, 35,4, 8/1990. 5. Xuewen Wu, Xianfeng Huang, Guohua Fang, Fei Kong (2011), "Optimal Operation Land & aWter Management inhe t Flood of Multi-Objective Hydropower Reservoir with Ecology Consideration" Journal of Water Resource and Protection, 2011, 3, 904-911 Affected Areas of Assam: A Casetudy S in 6. Yeh W. W-G. (1985). "Reservoir management and operations models: A state of the art review." Water Resour. Res., 21(12), 1797-1818. Dharmtul — elliN Area under Morigaon 7. Yeh WW-G. (1992), A stochastic inverse solution for transient groundwater flow: Parameter identification and reliability analysis, Water Resour. Research., 28(12), 3269- District, Assam 3280, doi:10.1029/92WR00683. ...

8. Zambelli M.S.(2009). "Long-term hydropower scheduling based on deterministic Jiten Malakar nonlinear optimization and annual inflow forecasting models". Divisional Officer, Soil 9. Dr. Reddy J.R. "A Text Book of Hydrology". Laxmi Publishers, Third Edition. Conservation Division Nagaon, Assam

n n n 1. Introduction: The.area identified for the study represents a trap between two rivers namely killing coming from south to north-west direction and Kapili coming from north east to North West direction. Drainage congestion, siltation, flood and the problems of water logging have been the regular/ recurring phenomena in the area in the recent past. As a result of such phenomena,. the people and their occupational base have experienced number of notable changes. The area which cultivators used primarily for kharif crop in the past, the same is no longer fit for growing kharif crop due to growing waterlogged scenario. As a result there is land-use change as well as occupational change. Grassland (wet) which was the basis of livestock base livelihood till 70's, the same has changed to cultivation base livelihood dominated by mono cropping in particular. Under cultivation, the possibility of putting land for use twice in a year (double cropping) has not been possible for most part of the area remain under waterlogged situation during entire kharif season. The land holding of majority being tiny (small & marginal farmer) production from a single crop has been inadequate to sustain the livelihood. These lie as the root causes for poor economic status of the local people. Poverty has been a common phenomenon. The economic vulnerability of the people caused by both natural and manmade phenomenon is possible to be addressed provided the waterlogged scenario of the area is mitigated.

13 14 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

2) Objectives: i) To identify the factors causing congestion of drainage channels and to identify adequate measures for decongestion. ii) To identify the factors causing degradation of natural water bodies and to suggest adequate measures for reclamation. iii) To identify the factors causing water logging, backflow of water during floods and to identify appropriate mitigation measures. 3) Methodology: Both primary and secondary data are collected from different sources. The change detection in landuse land cover are analyzed from toposheet for the year 1956-57 and for recent landuse land cover from satellite imagery (LISS-III, P-6) for the year 2009-10. The land classification are identified using NDVI (Normalized Difference Vegetation Indices) techniques, visual interpretation and by field verification. All analysis are made in GIS platform using Arc GIS 9.3 and Erdas Image processing software. For this study the ERDAS Imagine V 9.1 computer software is used to develop a land use classification using IRSLISS III P-6 images for the year 2009 and 2010. Image processing supervised classification technique was also used and important land use features i.e. forest area, waste land, settlement, fallow land agricultural land etc. extracted on the basis of pixel variation and compare the results with the result came after on screen digitization. The intensity of flood is measured by the flood data of National Remote Sensing Centre, Hyderabad. All other demographic data are collected by field survey and the secondary demographic data are collected from Census of Indian. The measures for reclamation, restoration and other interventions are suggested as per principles laid down in the Manuasl of soil & water conservation. 4) Location: The study area falls in the Mayong Development Block of Morigaon District. In the global location, the area is located between 92017'0.70''E to 92021'17.12"E longitude and 2607'58.94"N to 2608'8.25"N latitude. In the three Gram Panchayat areas under Mayong Development Block namely; Dakhin Dharamtul, Silchang & Nelli. The area is accessible as the National Highway 37 borders to its south and also to its east. As per records of revenue administration, the study area is comprised of 19 revenue villages of which 17 are inhabited. The villages are namely Alisinga, Barjalah, Barkhal, Basundhari Jalah, Bhugduba Bill, Bhugduba Habi, Block No.8, Dahali Makaria, Dahuti Habi, Dakhin Dharamtul, Khulapathar, Matiparbat, Muladhari, Nizkhula, Sarumati Parbat, Silbheta, Palahguri.

15 16 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

5) Land Use and Land Cover: Land Use /Land cover as on April 2009 Category Area (in Hec) (Satellite Imagery, LISS III P6, April 2009 Agricultural Land (Khaffl 1447 Grassland 262 Water bodies 271 Boro Paddy 1288 Built-up Land 510 Total 3778 Land Use /Land cover as on December 2010 Category Area (in Hec) (Satellite Imagery, LISS III P6, December 2010 Agricultural Land (Kharif) 1447 Grassland 262 Fig.2 Average Annual Rainfall of Last Seven Years Water bodies 271 Waterlogged Areas 1288 Source : Hydromet Division, India Meteorological Department Built-up Land 510 Total 3778 6.2) Changing behavior of Climate: 6) Climates of the area: The rainfall behavior in the recent past has been changing from one year to another. 6.1) Current Climate: The study area ( Morigaon district) There also has occurred erratic pattern in the average monthly distribution of rainfall. experiences hot and humid The summer is being characterized by occurrence of unpredictable flood at some time climate with an annual average point and drought like situation/ rainless spell in the other. This is a phenomenon which rainfall of about 1600mm. It has the area never experienced in the past. The pattern thus is an exhibition of the beginning two distinct seasons, extreme of climate change. wet and extreme dry. Maximum 7) Vulnerability of the area: rainfall occurs during the month The area is primarily a trap between two rivers namely Killing coming from south to of June-July. Rainfall starts declining suddenly from the northwest direction and Kapili coming from north east to north west direction. Drainage month of September with congestion, siltation, floods and the problems of water logging have been the regular/ near'dry spell during the month recurring phenomena in the area in the recent past. of December & January and As a result of such phenomena, the people and their occupational base have experienced continues till February. The Fig.1 Average Monthly rainfall for Last Three Years number of notable changes. The area which cultivators used primarily for kharif crop in average monthly rainfall pattern Source : Hydromet Division, India Meteorological the past, the same is no longer fit for growing kharif crop due to growing waterlogged depicted in Fig.1 makes the point Department scenario. clear. There is further occurrence of fluctuation in the average annual rainfall pattern as can be understood from Fig.2.

17 18 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

(Map-5) (c) The satellite imagery (LISS-111 P6, April 2010-Map-3 & 4) further shows that the area recognized as waterlogged (34%) during December, 2010 is under cultivation of Winter Paddy locally known as Boro Paddy. d) The above confirms shift in the land use pattern. The transition is denoted from grassland (wet) to waterlogged areas during Kharif season (May to December) followed by Boro Paddy cultivation during January to April. The changes in land use between the two reference period (1965 & 2010) can be seen from Table-1. d) Siltation: The phenomenon of siltation is seen visually in the drainage system of the study area. Also seen the same in the water bodies and waterlogged area. Despite there is increase in the waterlogged areas due to raising level of the drainage outlet as well as blocking of the same by some manmade structures (cross bund). e) Drainage Congestion: Dimal which is a natural drain following accros the study area from east to west direction suffers from siltation from Killing & Kopili River in its confluence zone. The rise of bed of Dimal in the confluence zone has acted as natural barrier to the free flow of its water. The consequence is the increase of stagnant water (waterlogged) area stretching over the upper zone of Dimal. The manmade barrier like embankment along the Dimal, Kopili & Killing have been further factors causing waterlogged scenario in the study area.

Source : Assam Survey, Department of Revenue Administration & Land Records 8) Specific climate Vulnerability of the area: The following information is the basis of confirming the problems of study area. a) Occurrence of Flood: According to the information maintain by Indian Remote Sensing Centre, Hyderabad, there has occurred heavy floods 9 times in a period of 10 years (1998 to 2007) in the identified study area. Photo-1 Waterlogged Area Photo-2 Congestion of Dimal River b) Occurrence of Drought: According to the local people of the area, they experienced droughts twice (2006 & 2007) in the same reference period. c) Water logging: a) The satellite imagery (LISS-111 P6, December 2010) shows that 34% of the total area is Water-logging and 7.15% is waterbodies. b) 45 years back the same area except the water bodies was grassland (wet) as per Survey of India Toposheet, 1965-66.

19 20 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Table: 1 Landuse Changes in the Study Area between 1965-66 to 2010 Category Area (in Hec) % Change Remarks Toposheet (Satellite Imagery, of Area 1965-66 LISS III P6, 2010 Agricultural Land (Kharif) 1383.85 1967 30.00 Kharif Land Increase Grassland 1726.42 52 85.40 Grass Land Decrease Mud 69.57 0 - River 87.2 - Settlement 265.02 - Waterbodies 245.94 271 9.25 Increase Boro Paddy - 1288 100.00 New adaptation TOTAL 3778 3778 Source: NRSC & Survey of India

Map. 4 Satellite Image view of the Study Area during December 2010

Map. 3 Satellite Image view of the Study Area during April 2009 Map. 5 Land Use Land Cover Map of Study Area

21 22 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

As an impact of the change that has occurred in the study area; there is land-use change Table: 3 Occupational Characteristics as well as occupational change. Grassland (wet) which was the basis of livestock base Particulars Numbers % livelihood till 70's, the same has changed to cultivation base livelihood dominated by mono Total Population 15360 - cropping in particular. Under cultivation, the possibility of putting land for use twice in a year (double cropping) has not been possible for most part of the area remain under waterlogged Total Working Population 5370 34.96 situation during entire kharif season. The land holding of majority being tiny (small & marginal Total Main Workers 3582 23.32 farmer) production from a single crop has been inadequate to sustain the livelihood. These lie at the root for poor economic status of the local people and poverty has been a common Total Marginal Workers 1788 11.64 phenomenon. The economic vulnerability of the people caused by both natural and manmade Total Non Working Population 9990 65.04 phenomenon is possible to be address provided the waterlogged scenario of the area is mitigated. Occupation 9) Target group analysis: Total Cultivator 3106 57.84 As a result of land use changes there is occupational change influencing the livelihood Total Agricultural Labour 651 12.12 pattern. The livestock based economy has changed to agriculture. (cultivation) based economy. Total engage in Household Industry 114 2.12 The landholding pattern on the other hand being tiny (small & marginal) for high majority, there has occurred stress and difficulties to assure livelihood from cultivation based economy. Total Others 1499 27.91 These phenomena have affected nearly all dwellers of 17 out of 19 inhabited villages. These Source: Census of India 2001 villages according to 2001 census records of India, houses 15360 population distributed in 2797 households. The size of the household is relatively bigger than the all Assam average. Of the total population of 17 inhabited villages out of 19 villages, the working population By social group, 60.19% of the population represent the general caste population, 16.54% constitute little over one third of the total (35%). The phenomena of marginal worker constitute ST's and 23.27% SC's. The adverse impact of the changed situation has been reflected in another one-third of the total working population. The dependency status thus is of higher the BPL census 2002 as 60.71% of the total households are reported to live below poverty order accounting 65.04% of the total. line (Table-2). A keen look at the occupational pattern indicates extremely high level of dependency on Table-2: Household & Population b Social Group. agriculture (70%) with cultivator accounting 58% and agriculture labour accounting 12%. Labour absorption in the household level industrial activities is at the minimum accounting a Particulars Numbers % mere 2% of the total. The engagement in others category after agriculture is the occupation Total House hold 2797 for 28% workers. The occupational structure once again provides the linkage of high majority of the working population with that of the crop based agriculture which has been exposed to Total Population 15360 - vulnerability caused by the natural and man-made factors. Average Household Size 5.49 - 10.Core problems and causes: Social Composition 10.1 Core problems: General Cast Population 9245 60.19 The core problems identified in the study area includes water logging, siltation, drainage Schedule Caste Population 3574 23.27 congestion and backwash flood. An explanation of the causes is outlined below- Schedule Tribe Population 2541 16.54 10.2 Causes : BPL Family*1698 60.71 Water logging: a) The satellite imagery (LISS-111 P6, December 2010) shows that 34% of Source: Census of India 2001 the total area is Water-logging and 7.15% is water bodies. b) 45 years back the same area except the water bodies was grassland (wet) as per Survey of India Toposheet, 1965-66. c) * BPL Census 2002 The satellite imagery (LISS-111 P6, April 2010) further shows that the area recognized as waterlogged (34%) during December, 2010 is under cultivation of Winter Paddy locally known

23 24 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 as Boro Paddy. d) The above confirms shift in the land use pattern. The transition is denoted 11) Negative impact of the Problem: from grassland (wet) to waterlogged areas during Kharif season (May to December) followed by Boro Paddy cultivation during January to April. The changes in land use between the two The negative impact of the scenario is seen in the cultivation of kharif crop. The water reference period (1965 & 2010) can be seen from Table-1. remaining stagnant in the area for entire summer, the possibility of putting land cultivation. Even when farmers out of zeal put some of the fringe areas under cultivation, the danger of Siltation: The phenomenon of siltation is seen visually in the drainage system of the study uncertainty of reaping safe crop remains as the overarching psychque. While the chances of area. Also, the same is seen in the water bodies and waterlogged area. Despite there is double cropping are missed, psychological demotivation of the farmers has been another increase in the waterlogged areas due to raising level of the drainage outlet as well as blocking negative factor of the scenario. of the same by some manmade structures (cross bund). The mouth of Dimal river being rising due to the siltation of Kapili and Killing rivers backflow Drainage Congestion: Dimal which is a natural drain following accros the study area from of flood water has caused another negative As a result of interplay of the three rivers, there east to west direction suffers from siltation from Killing & Kopili River in its confluence zone. has emerged an expansion process of waterlogged area. Consequently, the size of kharif The rise of bed of Dimal in the confluence zone has acted as natural barrier to the free flow crop area is decreasing gradually. The decreasing trend of kharif land thus is another negative of its water. The consequence is the increase of stagnant water (waterlogged) area stretching impact of the flood led waterlogged scenario. over the upper zone of Dimal. The manmade barrier like embankment along the Dimal, Kopili & Killing have been further factors causing waterlogged scenario in the study area. Further, the flood led waterlogged scenario has another negative impact on the livestock based economy of the people. Most part of the present waterlogged areas was shallow water Backflow effect of flood: The area identified for the study represent a trap between two grassland earlier. The grass has decreased over the years with increased depth of water. rivers namely-, Killing coming from south to north-west direction and Kapili coming from north east to north west direction. As on when there occurs flood in the two rivers, there is With shortage in green fodder, consequently livestock economy is nearly in the verse of backflow through the outlet channel of Dimal. The intensity of waterlogged scenario increases extinction now. with more and more area coming under water (Map.6). Waterlogged scenario / status starts declining from the month of December and with this the scope of putting land under winter cultivation begins. Unfortunately, the possible period of use land for cultivation last for five months (up to April).Thus, the cultivable season being restricted only for few months. While double cropping is not possible in a short period; growing high value crop of long duration also does not exist. Tiny holding sizes of the farmers are another compelling ground. There is thus negative impact in the generation of agricultural production enough to meet the minimum livelihood needs of the farmers. 12) Adoption aimed : After making the study area free from the identified problems through the identified interventions; there opens the scope for undertaking following practices at household level. (i) Double cropping practices. (ii) Crop diversification. (iii) Farm forestry & fodder cultivation (iv) Integrated farming like Fish cum Paddy and Fish cum Duck/Piggery. 13). Goal (outcome), outcome indicators and target groups 13.1) Outcome:

Map. 6 Flood Scenario of the Study Area To build the resilience of the affected population to the vagaries of natural and manmade Source: National Remote Sensing Centre, Hyderabad factors in the area.

25 26 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

13.2) Outcome indicators: 14.2) Activities & investments: a) Flood damages in the affected area reduced. Unit Cost of Intervention: b) Water logging reduced and land available for farming SI. Intervention Size of Unit Cost No. Unit Rs. in Lakh) c) Surface irrigation made available from tapping water from the drainage lines through 1 Reclamation of wetland 1 Ha. 0.22098 check dams and other measures 2 Desilting / decongesting of drainage channel 1 m3 0.000725 d) Income of the affected population increased through adoption of improved farming 3 Diversion wire for water distribution 1 No 9.1 practices 4 Diversion drain structure for draining out excess 1 No 0.6128 14). Results and Activities: water 14.1) Results (outputs) : 5 Preventing back flow by setting up sluice gate 1 No. 145.60

1. Agriculture land reclaimed and developed for cropping with irrigation S1. Activities to support Total People's Funding 2 Participatory Land Use Planning Developed and Implemented No. Cost Contributions Qnty. (Rs. in (Rs. in Lakh) (Rs. in 3. Agricultural, horticultural crops grown, fisheries and livestock production practiced Lakh) Lakh) Interventions aimed How the Interventions will help in 1 Preparatory & Administrative Cost Land & Water Management a Household Benchmark Survey 2.00% 10.008 - 10.008 • Reclamation of wetland • Promote aquaculture b Development of MIS 0.50% 2.502 - 2.502 • Support Plantation of waterlogged c Project Management Staff 5 Nos 42.76 - 42.76 resistant Tree species d Engineering Survey 5% 25.02 - 25.02 • Promote Horticulture e Administrative Overhead 5% 25.02 - 25.02 • Desilting / decongesting the • Facilitate free flow of water (including cost of vehicle) drainage channel f Institutional & Capacity Building 5% 25.02 25.02 • Diversion wire structure for water • Increase production of Kharif and Sub Total of 1 130.33 0 130.33 distribution. (Indicate in the Boro paddy Promote Horticulture 2 Work Phase drainage map) • Promote cultivation of winter crops a Reclamation of wetland 271 Ha 59.89 5.989 53.901 b Desilting / decongesting the 247500m3 179.4 17.94 161.46 • Increase surface flow irrigation drainage channel Potentiality c Diversion wire for water 10 Nos. 91 9.1 81.9 • Diversion drain structure draining • Facilitate free flow of water distribution out excess water • Reduced waterlogged area d Diversion drain structure for 40 Nos. 24.51 2.451 22.059 draining out excess water • Increased Fodder cultivation e Preventing back flow by setting up 1 Nos. 145.6 14.56 131.04 • Support Live stock rearing sluice gate • Preventing back flow by setting • Mitigation of flood during summer Sub Total of 2 500.400 50.040 450.360 up sluice gate • Reduced waterlogged conditions GRAND TOTAL 630.730 50.040 580.69 during winter

27 28 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

12. Log frame Action point Expected Goal Link with Land & Water Management Desilting / decongesting of • Reduced water logging • Increase Cropping Management of aWter Resources ofhe t drainage channel à • Flood Mitigation à Intensity • Surface flow Irrigation • Increase Crop Yield North East Region with Specialef Rerence • Crop Diversification Reclamation of Wetland • Reduced water logging • Increase Fish Production à • Aquaculture à • Facilitate Horticultural to Assam • Horticulture Plantation • Plantation of waterlogged • Small livestock production resistant Tree system à à • Fodder Cultivation Er. Ramesh Ch. Borah • Livestock rearing Senior Consultant, NEDFi, Guwahati Construction of Diversion wire à • Increased production of à • Surface flow irrigation Drainage & Landscape Development Expert for water distribution Kharif & Boro paddy facilities Former Chief Engineer, W.R.Deptt., Assam Construction of sluice gate • Preventing back flow • Increased in Agricultural • Reduced water logging Land • Water storage during winter 1. Introduction : References: The North East Region of India is a unique gift of nature to the people. Originally the North • Gurmel Singh, Manual of Soil and Water Conservation Practices, Oxford & 1BH East Region meant the Seven Sister states of the region i.e. Arunachal Pradesh, Assam (the Publishing Company, 01-Apr-1991 mother state), Manipur, Meghalaya, Mizoram, Nagaland and Tripura. When the river basin concept came into existence, the region extended its coverage to the state of Sikkim and the • Sastry G, Venkataramana, Gurmel Singh, Manual of Soil & Water Conservation northern part of West Bengal. These being parts of the Brahmaputra basin, made this region Practices, Oxford & lbh Publishing Co Pvt Ltd unique with their beautiful landscapes ornamented by mountains and valleys, hills and fertile • R.P.C. Morgan, Soil & Water Conservations, National Soil Resources Institute,Cranfield plains and the intensified natural drainage network connected directly or indirectly to the University mighty Brahmaputra. The nature made the region rich in natural resources. The bio-diversity • Soil and Water Conservation With a Focus on Water Harvesting and Soil Moisture of the region stunned the world and had occupied the most prestigious position in the world Retention, Compiled by: Deborah Duveskog, Contributors: Mbeere Farmer Field scenario. The region's seasonal climate and drainage network made it rich in Water Resources Schools Daniel Nyagaka , Benjamin Mweri, Mwamzali Shiribwa, Dr. Pascal Kaumbutho which play a vital role in the socio-economic development and overall prosperity of the people. In spite of the region being blessed by nature with fertile landmass, immense water and • Vulnerabilities have been confirmed through reconnaissance survey and adopting world recognized mega biodiversity hotspots; it is among the poorest regions of the country participatory rural appraisal method and analysis of various data sources like rainfall facing hard-to-keep pace of development compared to other parts. Though the natural data, satellite imagery etc. resources are available, the resources are not fully explored/ harnessed. The Water Resources is the most vital resource of the region. Out of different forms, the river flow induces hazards n n n off and on and puts setback to the region's economy because of lack of proper management. The infrastructural development in this region is primarily subjected to the natural calamities such as earthquake and it's after effect in the entire region; recurring floods in the valleys and landslides in hilly states. In addition, the infrastructure development in the region is also being affected due to increase in population density and widespread poverty among the growing mass.

29 30 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Water availability in the region is subjected to temporal and spatial variation, plenty in Sl. Potential Estimated value plains during the monsoon season. Nearly 80% to 90% of water is available in the drainage No. network in that period only. Most of it appears as river flow through hills and plains and 1 Total Water Resources Potential 30% of India's total ultimately merging with the sea. The state institutions dealing with Water Resources management are continuously trying to manage the temporal peaks but are unable to properly 2 Per Capita and per hectare water availability Highest in the country administer because of their poor financial condition. As a result, it comes and goes away 3 Hydropower potential About 41% of the country's total without much utilization. On its course it damages the valley's economic & social development structures by creating floods and also creates natural disturbances in the hilly states. 4 Hydropower potential developed so far Only about 3% 5 Irrigation potential 4.26 million hectare(m.ha) The economic and infrastructural growth of the region especially of Assam is dependent on the behavior of the region's Water Resources. The recurring flood is a part and parcel of 6 Present coverage of irrigation 0.85 Million hectare (m.ha) (20% of the this natural asset which is influenced by climatic changes of the region. Although the flood existing potential against the national maintains the year schedule, yet the frequency and magnitude becomes erratic. Moreover, average of 56.4%) the high silt laded energized flow in each wave gradually changes the morphology of the river 7 Ground water potential Very high in valley areas (available in altering the rivers' flow section. The increase in magnitude of the wave enhances the degree shallow depth of damage in the flood plains. 8 Potential developed so far 4.3% Basically, Water Resources management of a basin means the best use of land and To manage this huge asset many factors influencing the regional structure like: - i) Geology water in elevating the people's living standard, reducing poverty of the growing mass and of the region; ii) Its climatic conditions; iii) Hydrology i.e. fluvial behavior of the rivers; iv) Soil enriching the environment or maintaining the environment statuesque without further qualities and its distribution in the flood plains and hilly areas; v) Agricultural practices (i.e. deterioration. To achieve this, integrated Water Resources management is utmost necessary. Traditional & Modern techniques such as cropping pattern and irrigation); vi) Environmental The state of Assam has been affected by chronic floods and change of river geometry leading aspects; vii) Hydropower development; viii) Social, Political and Administrative system of the to reduction of land mass. Both the floods & change of river geometry together gives a set NE states; and ix) Navigation & Transport system, are to be thoroughly examined to ascertain back to the state. The synchronized floods in the Brahmaputra and in its tributaries usually the potentials and identification of flood induced natural hazards. Further, appropriate make both valleys of Assam to reel under flood. To reduce the flood damage, land-loss and technology needs to be adapted to harness and manage. Since, the state of Assam is presently the flood risk associated with infrastructural development, integrated flood and erosion facing a burning problem of flood & erosion resulting in recurring set back to the state's management is of topmost priority. economy the integrated flood & erosion management is right tool for protection of the people and their properties and simultaneously elevating their economic status. For an all-round development of the region, proper management of monsoon flood related hazards along with best use of land and water parallel to development of other natural 3. The Stsyem : resources are utmost essential. The region is based on agricultural economy. So, the flood The name itself means the son of Brahma .It originates in Tibetan region of China and risk free agricultural crop planning is the time-need to utilize the rich fertile floodplain for more flows majestically in eastward direction till it crosses the Great Himalayas, which is younger production to meet the requirements of growing mass and elevate the living standard of the than the river, to enter the Indian Territory. It traverses through the stepping hills and the people of the region. mountains the constituents of southern Himalayas and crosses the tiny valleys within them to 2. Water Resources of the Region : appear in the plains of Arunachal and Assam and continues its journey through Bangladesh to meet the Bay of Bengal. The total length of the river is 2880 Km.. During its course, it The Water Resources of the region is basically dependent on seasonal rainfall occurring receives numbers of tributary multiplying its flow magnitude gradually. It forms the life line of in the region and its resultant runoff in the rivers including the input to the Brahmaputra the region. The river is popularly known as Bor-Luit in Assam. The drainage area of the river drainage system from the upstream countries as the river Brahmaputra and some of its excluding the drainage area of Barak, one of the major tributaries, is 5, 80,000 Sq.Km spread tributaries are international rivers. A brief idea of the region's water wealth can be obtained over four countries. The northeast states share is Arunachal Pradesh (41.88%), Assam from Dr. D. Goswami's (2001) estimation of Water Resources of the basin as represented in (41.88%), Meghalaya (6%), Nagaland (5.55%), Sikkim (3.75%) and West Bengal (6.47%). table below: The longitudinal gradient of the river shows wide variation the steepest in the last part of

31 32 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Tibetan journey, steep in system has flood flows and often occurs in waves generally 5 to 6 waves. Inhabitants of the Arunachal and flatter flood plain have to fight with the flood for survival and also work in the flood plains for gradient in the plains of multiplying the agricultural products following the rainfall pattern and occurrence & Assam and Bangladesh. subsidence of flood waves. The steep gradient has energized the flow in the The retreating monsoon starts from the end of September to first half of November. Rainfall rivers within Arunachal. The during this period is negligible. Weather is clear and sunny. Pleasant month of the year and total energized flow in time for agriculture harvest based festivals of the region. Brahmaputra appears at The entire North East Region is in southern part of climatic Zone-I. It receives rainfall from the foothill and suddenly south west monsoon with seasonal variation 2%-5% during winter (i.e. Dec to Feb), 20%- begins to flow in flatter 35% from March to May during pre-monsoon, 66%-85% from June to September during gradient creating change in monsoon and 3% to 6% from October to November during retreating monsoon period. river morphology from the 5. Hydrology : single channel to multichannel braided one. The discharge hydrograph The river Barak has of the river indicate discharge individual basin area of fluctuations and different 42,455 Km2, about 62 per waves of flood during cent of which lies in the monsoon period. The waves North-eastern region of occur before subsidence of India. Out of the total length the previous wave and of 902 Km, 564 Km is within multiply its magnitudes. The north-east India. Source: Water Resources Department tributaries cannot discharge to the main river due to non- 4. Climate and Rainfall in the North East Region : subsidence of the waves and The varied seasonal climate influences the flow in the river system. The indigenous people copy the main river with of the region divide the year in six seasons depending on different weather and natural gradual rise of the flood environment -(a) Summer, (b) Rainy, (c) Autumn, (d) Hemanta, (e) Winter and (f) Spring. magnitude. The synchronizing Generally the climate of the valley is divided into four primary seasons- (a) Winter, (b) Pre flood of the tributary and the monsoon, (c) Monsoon or Rainy and (d) Retreating monsoon depending on the rainfall main river presents a picture influence. of overall damage to the flood plains all throughout the The winter season starts from late November and continues up to January having cold valleys. The mean annual spells and fog on the flood plains of the Brahmaputra. The cool mountain wind prevails. The flood occurs with a flood weather is generally clean and sunny. Very little rainfall occurs. Source: Water Resources Department frequency of two years return The pre-monsoon is the transition period between winter and monsoon. Rain occurs period. The highest ever recorded flood at Pandu of 72,748 m3/sec can be assigned as flood occasionally. Winds become strong in the valley and the indigenous people name it as of 100 years return period. From 1954 till 1996, 12 devastating floods were recorded and "Bordoisila". Rapid changes in atmospheric temperature and induces a rising trend. from 1996 onwards the floods in the valley has a increasing devastating trend, occurring almost every year either by breaching the embankments or overtopping it. The recent flood The monsoon season starts from second half of May and continues till September. It is waves are caused by climatic changes in the rainfall patter though total annual rainfall remains the season of traditional agricultural activities in the flood plains. The rising temperature is same. The average discharge of Barak River is 694 cumecs at Badarpur which occasionally cooled down by continuous heavy rainfall. This rainy weather continues for days. The river rises up to 7764 cumec during the flood season (D.Goswami, 2006).

33 34 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

6. Water Resources Management : drainage system to produce economical, abundant power for the nation, economic benefits The detailed information relating to the above discussed points will form the base for through power export, employment generation, flood control etc. The unique characteristics better Water Resources management plan and program. Integrated Water Resources of the Northeast and the past lessons from the large dams demand to examine critically management involves the best use of land and Water Resources. The resource can be these potentials claimed by the proponents of the large dams. Though the hydropower utilized for development of Hydropower, Agricultural activities, Industrial development and generation can provide ample scope for flood moderation in the valley portion the multi- other socio-economic upliftment. Since, the region's economy is based on agriculture; the benefit project should therefore be planned. But, the present political and administrative best use of Water Resources is of primary importance. The traditional agricultural activities scenario is perhaps not favouring the goal of such plan. are dependent on rainfall pattern and the nature has provided ample scope for these activities The rivers, beels, wet lands and marshy lands in the valleys provide ample scope for by showering in the hills and plains in abundance in time. The modified cropping pattern pisciculture. The region has numbers of such areas where different species can be cultured needs irrigation to supplement the deficiencies of water which can be met up from ground for meeting up regional demand. The individual states are still working in this area . Water Resources or surface water in the rivers, beels, marshy lands which are the natural stores for the purpose. The region so far develops 0.7 million hectares out of 3.7 million Every development in flood plains should be free from flood risks. The valleys within hectares and has potential to utilize more. The modified cropping pattern with inputs like Assam are receiving the flood flow as an annual event during the period from May to October. fertilizer, irrigated water and pesticides will enrich the state granaries to feed the growing The synchronizing floods in both the main river and the tributaries creates a critical situation mass. The states are to work more in this field. displacing lakhs of people and damaging crops and sometimes halting the agricultural activities The agricultural flood plain are to be protected locally from the recurring floods for use in and also other important activities. The river/river systems sometimes/often behave the cropping season by constructing embankments on river banks as per existing guidelines independently/separately bringing flood miseries to the areas of the respective floodplain. of Indian Standard Institution. Though these local protections favour change of channel The Central Government of India, based on recommendation of Rashtriya Barh Ayog and geometry, the benefits accrued from it is most remarkable than the effect of the embankments Working Group on Flood Management for Tenth Five Year Plan issued instructions for on the rivers. The objectives of construction of the embankments can be fulfilled if the assets constructing reservoirs with flood control as overriding aspect in the multipurpose dam project already created are kept fit to match the changing morphology and fluvial behavior of the giving different benefits to the people. river. The life of embankment will thus be increased due to such measures. The Brahmaputra Board had prepared basin-wise Master Plan incorporating multipurpose The living standard of the people can be elevated with the use of economical & eco- projects in the basin considering benefits on different sectors with special attention to flood friendly energy which can be produced enormously in the region through hydropower control sector. It brought out that "the key to a long term and reasonably permanent solution generation using the river flow within the stepping hills and mountains and also in tiny valleys of the flood problem of the Brahmaputra valley lies in constructing some large storage of the region. It is evident that the surface water potential for hydropower generation available reservoirs (R. Rangachari 2006)". This effective and reasonably permanent solution to the in the north eastern region is of very high order comparing to the country's potential and that long standing flood problem of the Brahmaputra valley is therefore most important as no too is flowing in deep gorges in upper reaches of the main river and the tributaries well within other measures like embankment, afforestation and watershed management would country's boundaries. This envisages that there is possibility of reaping the high benefit of independently contribute as much to the reduction of flood problem in the valleys. hydropower generation as the topography permits but harnessed very little. The north-eastern states together installed hydro-power projects with installed capacity of 1089.3 MW which is The Rashtriya Barh Ayog (RBA) in its 1980 report pointed out that the approach to the only 3.2% of power potential of 31857 MW of North Eastern Region. Poor financial health of problem of floods must be a part of the comprehensive approach to the best possible utilization State Electricity Boards in this region is the major roadblock in the development of this sector. of the land and Water Resources. It asked that various alternative measures should be The Brahmaputra Board draws a scenario of reaping the hydro power potential of 31857 MW considered for flood management. It recommended, inter alia, that reservoirs, to the extent of of North Eastern region, out of which 26756 MW from Arunachal alone, Assam 351 MW, physically and economically feasible, must be considered as an important component in any Manipur 1176 MW, Meghalaya 1070 MW, Mizoram 1445 MW, Nagaland 1040 MW, and package of measures. It advocated that a river basin is the most suitable unit for flood control Tripura the lowest 9 MW. This most economical energy coupled with other types of available and Water Resources planning (R. Rangachari, 2006). energy can be used for enhancing industrial development which will remove the backwardness of the region. "Two decades have elapsed since the Master Plan was made and the investigations for many possible schemes to implement it had also been completed. Unfortunately there is no The Northeastern Region is currently charting a course of development and large hydel significant progress on any of the follow up actions on the Master Plan or on implementing projects for power export. It is a part of the development plan-exploiting the country's perennial the RBA (Rastriya Barh Ayog) recommendations. The existing institutional mechanisms to

35 36 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 reconcile differences and coordinate and integrate efforts of different states of North-east, devices as tried in these places is till now not capable of containing the river or driving away such as North Eastern Council or the Brahmaputra Board have their own weaknesses and the course from the bank. The continuous firm bank with the use of modern construction problems. Meanwhile, expert groups that went into the problems of the Northeast have materials like geo-textile products need to be developed. The primary aspect in such protection reiterated that the validity of the past recommendations and urged for actions to implement plan is to protect the bed and bank below LWL to stand the bank in its statuesque. Detailed them (R. Rangachari 2006)." investigation on geo-morphology of the bank needs to be carried out with proper planning and design. The Task Force set up after the devastating flood of 2004 in Assam, states that "reservoirs are rightly called long term solutions for mitigating the problem of floods". Taking into The recent use of RCC porcupines in river management gives comparatively better result consideration of the large benefits that accrue from reservoirs, the Task Force reiterates the in containing the river erosion but it requires longer time to fulfill the objective. The use of views of the RBA and recommends the taking up the reservoir projects of required dimension Jack-Jetty and submerged vanes in controlling erosion are also not the solution for erosion in Brahmaputra and Barak system of rivers. It is essential to have specific flood cushion control as it hampers navigation and aquatic life and creates more area on upstream and allocated in all relevant water related projects and ensure the projects are designed for optimal downstream erosion prone due to migration. capacity especially from flood moderation angle, keeping in view the opportunity for suitable The erosion of banks of the Brahmaputra River explains that nothing is certain & guaranteed projects at optimal storage sites is not lost (R.Rangachari 2006). in river protection as the state institutions are trying to tame the mighty river & its nature which "It found that generally the recommendations of RBA had not implemented by Government. is unpredictable & uncertain yet. Our knowledge, experience & studies only give a probability Thus, it is not surprising that floods regularly continue to wipe out whatever infrastructure is to yield desirable result or at least reduce the extent of damages. Hence, the established created and nullify beneficial economic developments. The crucial challenge in the developing techniques must be adopted to prevent the investment loss and further deterioration. Northeast will be to provide first a reasonable degree of flood protection. As already noted Navigation aspect is one of the important beneficial aspects of Water Resources many suggestions in this regard have been made by many expert bodies and accepted in management. Waterways have played a significant role in the development of trade and principle. The implementation of the accepted recommendation has, however been very poor. industry in the northeastern region in the past. For centuries, the Ganga, the Brahmaputra This is the first challenge in the development arena for the northeast (R.Rangachari 2006). and the Barak-Meghna served as arteries of trade in this region. The countries of Ganga The recent developments in harnessing the benefits of the hydropower sector have virtually Brahmaputra Meghna region have since realised the importance of restoring Inland water been wiped out the flood moderation aspect from multipurpose projects in the region. Since transport in this part for mutual benefit. The Government of India has given importance to the these measures are not coming up to the appropriate level the state of Assam has to reel tremendous scope for the development of Inland Water Transport in the northeastern region under flood and therefore has to provide local protection to the flood affected people by low- of India and had recently planned to revive National waterways on the Ganga Brahmaputra cost fruitful measures like embankments and developing the flood absorbing pockets like Meghna Rivers. Hence, all plans for Water Resources development based on the Ganga, beels, wetlands and abandoned courses of the river. Brahmaputra and Meghna should holistically integrate the needs of IWT and make inland navigation as part of the comprehensive planning. The Navigational Sector will be improved The other important aspect of management of flood is the reduction of land loss due to by the possibility of plying large vessels in the Brahmaputra up to Murkongselek throughout change of river configuration by erosion of the bank and failure of local protection i.e. the year and substantial benefit is at the reach. The crossing of the river by 19 present embankments. To address this problem established techniques of protecting banks and established routes in entire course of Brahmaputra in Assam facilitate about 35 lakhs of vulnerable embankments can be adapted. Though, the state institution is applying such people and trade of approximately 60,000 tons of cargos by ferry services. The best use of technique in selected areas, the area affected is much more than the area attended. This the existing navigation facilities from state to state and from different countries is to be explored requires enriching the state allocation towards flood and erosion management program. immediately (C.D.Mahanta). Moreover, the state institution nowadays follows the so called modern technology with different construction materials without proper planning and proper justification of the use of materials The above discussion is primarily about the structural measures required to train the rivers in right place with proper specification. The proposal forwarded to the higher authority needs in the region for managing flood and flood related hazards, but non-structural measures like more intervention at erosion points rather than use of the materials on strengthened flood forecasting and warning, flood plain zoning and flood proofing are to be integral part for embankment slopes. minimization of losses and reduction of the recurring expenditure on flood relief. Strict regulation of settlement and economic activities in flood plain zoning reducing the loss of life and The Vaishnavite cultural centre i.e. Majuli, the world famous river island and South Salmara, properties is top most priority. The Task Force 2004 also recommended that flood plain zoning the valley's lower most portions within Assam, need proper erosion resistive measures should be actively followed by all the states and necessary laws/regulations for this purpose protecting the banks to reduce further land loss. The flow diversion measures and pro-siltation

37 38 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 should be enacted and implemented by the state governments. Though the State Governments per established technology. The use of construction material other than traditional one should of the North-East region is taking up steps following these instructions, yet much is to be be thoroughly examined and its performance for long duration may be assessed. In absence done to achieve the goal. of flood moderation in multi-purpose projects/ hydel projects, conventional practice of flood and erosion management is to be adapted and strengthen the existing weak ones. The trial To fulfill the main objective of management of the Water Resources of North East region full co-operation between the sister states and governments both central and states is the and error method for adopting measures to reduce land loss should be judicially selected. primary need. The co-ordination between the line departments of individual states of the The coordination between the departments alias the states is a must for success. The capacity region is another aspect for better management. Moreover the involvement of communities of the state institution to implement the program is to be developed. in the areas of structural intervention and taking active part in non-structural measures will References : bring success to the integrated Water Resources Management program 1. The Brahmaputra Basin Resources, Water Science and Technology Library, Volume 47 Integrated flood management integrates land and Water Resources. Development in a 2. Conservation and Management of Water, Challenges and Opportunities in the Northeast river basin takes place with a view to maximizing the efficient use of flood plain and minimizing India, R. Rangachari (2006) the flood damage, the land loss and loss of life. As basin approach is time consuming and inter-state dimension, and the present set up of flood management infrastructure often fails 3. Development and Growth in , The Natural Resources, Water and to provide protection, the State has to encourage the community participation in integrated Environment Nexus, Strategy Report June 2007, Report no 36397-IN (World Bank) flood management. So, it becomes an integrated part of integrated component of flood 4. Brahmaputra River, Assam, India, Physiography, basin denudation and channel management. In other words, community participation becomes fundamental and essential aggradation. Water Resources Research, Volume 21-Dr.D.C.Goswami for each stage of the management i.e. preparedness for, response to and recovery from the flood damages. Community participation provides ample scope for Water Resources 5. Fluvial regime and Flood Hydrology of the Brahmaputra River, Assam, Memoir Geological development within the context of Integrated Water Resources Management. The benefits Society of India No-41 -Dr.D.C.Goswami are derived at various levels of social and economic activities through development of policy 6. Mechanics of Sediment Transportation and alluvial stream problems-R.J.Garde & K.G. and land use planning. In absence of organized community, which is the present status of the Ranga Raju state, most activities are carried out at individual or household level driven by individual necessity. The limited effectiveness and insufficiency of such activities cannot provide protection to the community and individuals from the adverse effect of flood. If the activities, n n n carried out at individual initiatives are pooled together and carried out in an organized manner at the community level, risk and vulnerability due to flood can be substantially reduced. The present trend of the people's thinking is that, everything is government's responsibility, which will be rectified by community participation. The State institutions particularly in Assam are quite efficient to take part in the Management Program; still it requires building their capacities to carry out the Management Plans. The institutions are now in view that a group of likeminded technical or non-technical people are capable to carry out such programs. The dedication of the group selected must act in an organized manner to prepare the plan, design the components and carry out full proof plan without interference of higher communities or political hands. 7. Conclusion : Every one probably knows that good plan shapes good decision. That is why good planning helps to make the Water Resources management successful. The planning must be good enough to fulfill the objectives. The Integrated Water Resources Management which maximize the efficiency of land used and Water Resources available in the region must be introduced. The Integrated Flood & Erosion Management through structural intervention should be as

39 40 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

line modification takes place during the falling stages when excess sediment is deposited as bars within channel, causing a change in local flow direction and migration of the thalweg. During floods, because of certain change in river configuration, the channel starts shifting at some vulnerable reaches, which in turn induces bank erosion. As a consequence, the river is River Bank osionEr Management in Assam hardly predictable and highly unstable. The aggradatioal trend of the bed of the river since the 1950 flood combined with intense braiding, large discharge and heavy sediment has been the key factor in causing the river extremely unstable at some vulnerable points like Nagaghuli, Maijan, Majuli, Bhairabpur, Sri Uma Baruah Dr. Rajib Kumar Goswami Balikuchi, Kaziranga, Howlighat, and Palasbari. Moreover, there is a tendency of the river to Additional Chief Engineer, Assistant Executive Engineer, shift southward within the valley reach. The tendency has become more prominent after the Water Resources Department Water Resources Department great earthquake of 1950, which raised the whole landmass of the northeastern part of the valley, particularly north of the Brahmaputra river including Himalayan foothill region by 3 to 4 meter. This southward thrust has initiated widespread erosion in the south bank near the ABSTRACT: Dibrugarh town and it is still continuing at different reaches even after taking various anti- erosion measures. The flood plains of Assam have the highest drainage density in the world and shelter a huge population. In recent decades, river bank erosion in the floodplain has become a serious Erosion Affected Reaches in Assam : threat to the population and highly cultivable fertile land. A large part of this landmass has The Water Resources Department, Govt. of Assam has identified as many as 25 such been already lost and the process is still continuing. In this paper, an attempt has been made acute erosion affected reaches within the main stem river Brahmaputra in Assam. to highlight the issue and the strategy adopted by the Government agencies to mitigate the problem. Introduction : The valley portion the Brahmaputra River is facing a heavy loss of landmass due to river bank erosion and change/migration of channels. This is a major hazard in the state and it has lost about 7.4% of its land mass due to this process. In fact, it is a bigger disaster than annual flooding. The loss or the discomfort associated with annual flooding is temporary. But, river bank erosion has a long-term impact on the economy and causes direct poverty. Once a part of the well developed land is lost due to bank erosion, it is gone for ever. Further, the state doesn't have proper mechanisms for compensating the people who loss their land due to erosion. Some of the important factors responsible for the severe bank erosion are (i) Rise and fall of the river water (ii) Number and position of major channel active during floods (iii) Formation and movement of bed-forms (iv) Cohesion and variability in composition of bank materials, and (v) Intensity of bank slumping. The main stem river Brahmaputra consists of a number of differently sized channels, and Figure 1: Map showing the locations of very severe erosion in the Assam part of sand bars that change their location and appearance every year. The most significant bank Brahmaputra

41 42 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Significant Erosion Reaches of River Brahmaputra in Assam (Data Source: WRD) Erosion in Dibrugarh town (Data Source: WRD) Bank Reaches District Annual flood affected area 835 Ha South Chumoni Tinsukia Land area eroded (1967-2008), 491 Ha South Dhola Hatighuli Tinsukia (bank line length 25 Km) South Rohmaria Dibrugarh Rate of erosion 4.72 m/year Majuli Island Jorhat Number of household lost 768 Nos South Neamati Jorhat (Last 10 years) South Kaziranga Jorhat Number of household affected 4,036 Nos South Majuli island Jorhat Erosion in Matmara (Data Source: WRD) North Kareng Chapori, Arney Chapari, Matmara Dhemaji Annual flood affected area 6,252 Ha South Moirabari-lahorighat-Bhuragaon Morigaon Land area eroded (1967-2008) 3,640 Ha (Bank line length 13 Km) South Hatimura area near Jakhalabandha Nagaon Rate of erosion 69.2 m/year North Bishwanath-Panpur Sonitpur (Highest erosion rate is observed in 2007-08 at 161.86 Meter/year) South Palasbari-Gumi Kamrup Number of household lost 199 Nos South Mukalmua Nalbari ( Last 10 years) North Bohori-Baghbar Barpeta Number of household affected 2,186 Nos South Goalpara Town, Sonari-Hazirghat including Goalpara Erosion in Majuli Island (Data Source: J. N. Sarma, 2008) South Salmara Township Period First Second Third North Dhubri-Patamari Dhubri 1917 -1966 1917-1972 Mean 1966-1996 1972-1996 Mean 1996-2001 Erosion in Rohmoria (Data Source: WRD) Part west Part east Part west Part east Entire 0 0 0 Area of land eroded 8,435 Ha of 94 E of 940E of 94 E of 94 E Majuli Bank line length 9 km Average 1.19 km2 2.35 km2 1.77 km2 3.69 km2 0.01 km2 1.84 km2 6.42 km2 Average depth of erosion 800m annual (Erosion) (Erosion) (Erosion) (Erosion) (Silting) (Erosion) (Erosion) No of villages affected 16 Nos rate of No of tea gardens affected 6 Nos change No of house hold affected 1580 Nos Erosion in Kaziranga area (Data Source: WRD) Population affected 23,000 Nos Annual flood affected area 1,594 Ha Erosion in different period in Rohmoria (bank length of 16 km) Land area eroded (1967-2008) 491 Ha 1924 - 1967 43 51.92 sq km ( Bank line length 21 Km) 1967 - 1983 16 18.50 sq km 1983 - 1996 13 35.50 sq km Rate of erosion 18.46 m/year 1996 - 2001 5 4.95 sq km Number of household lost (Last 10 years) 238 Nos 2001 - 2004 3 1.00 sq km Number of household affected 2,613 Nos 43 44 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Erosion in Palashbari Town (Data Source: WRD) Annual flood affected area 3,340 Ha Land area eroded (1967-2008) 16,037 Ha ( Bank line length 25 Km) Rate of erosion 22 Meter per year Number of household lost (Last 10 years) 1,646 Nos Number of household affected 12,530 Nos Total area eroded in both banks of the river Brahmaputra Period Erosion in North bank (km2) Erosion in South bank (km2) Total area eroded (km2) 1912-28 to 782.49 747.61 1530.10 1963-75 1963-75 to 459.51 368.69 828.20 1996 1912 to 1996 1242.00 1116.57 2358.57 (Source: J. N. Sarma, 2006) Maximum shift in the Bank line in different locations of the river Brahmaputra in Assam Period Migration of North bank Migration of North bank Towards North Towards South Towards North Towards South Figure 2: The width of influence of the river measuresd from the middle of theriver of the first sequence of data (1912/28). The distances measured from the 1912-28 to 7740 m 8754 m 4810 m 7090 m datum to the south are assigned negative values). 1996 (Source: J. N. Sarma, 2006) Average 96.75 m/year (1916-1996) m/year 128.74 m/year (1928-1996) 58.66 rate (1914-1996) 87.53 m/year (1915-1996) Since the last 100 years the Brahmaputra shows a general trend of widening in Assam. As a consequence, it destroys more and more land and infrastructure including the old Location Auniati Satra of Ghumari Laokhoa Salmarigaon established system of flood embankments. The widening trend is clearly visible when Majuli (Morigaon district) comparing erosion and accretion rates over different periods. The erosion rate is three times (Source: J. N. Sarma, 2006) higher than deposition over a period of 15 years. In addition, some long-term observations about width changes of the Brahmaputra are available, even though from different authors and not directly comparable. The Brahmaputra occupied around 4,000 km² in the 1920s and expanded to around 5,000 km² by the early 1970s. A major avulsion (shifting of riverbed) upstream of Dibrugarh added many hundred additional square kilometers to the area within the river banks during the 1990s. Nowadays, the Brahmaputra occupies about 6,000 km² (source, WRD, 2008). It is very difficult to quantify the losses due to erosion. In general, it shows an increasing tendency. Reports available with Water Resources Department indicate that 3,860 km² of land were lost since 1954, with about 80 km² per year. The erosion wiped out more than

45 46 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

2,500 villages affecting more than 90,000 families, or nearly half a million people and 18 Index properties of flood plain soils (Majuli Island) important locations such as towns, heritage sites or tea gardens. 130 reaches are classified as being under moderate to severe erosion and 25 as very severe. A comparison between Type of soil Liquid limit Plastic limit Plasticity index the value of land lost to riverbank erosion and inundation flood damage between 1954 and WL (%) WP (%) IP (%) 1969 indicates that the costs of riverbank erosion were 35% to 85% of cost of flood inundation CL 50.8 to 37.0 23.1 to 18.9 23.7 to 19.0 damage. (41.7) (19.8) (21.0) Properties of the Riverbank soils: ML Non-plastic Non-plastic Non-plastic In general, the floodplain form and channel conditions can be regarded as a part of a temporal sequence related through transfer and storage of sediments from reach to reach. SP Non-plastic Non-plastic Non-plastic So, geomorphological explanations are incomplete unless they involve some understanding CH 72.6 33.8 38.2 of the properties of the materials. Soil resource mapping and taxonomic classification carried Source: R.R. Station WRD (1996) by the Natural Bureau of Soil Survey and Land Use Planning (NBSSLUP) indicated that the soils of floodplains of Brahmaputra lack in profile development and are deep to very deep, Values within the parentheses indicate averages. gray to mottled gray, imperfectly drained to well-drained, sandy to silty loam with coarse and/ Mechanical/Engineering properties of flood plain soils (Majuli Island) or fine stratification, slightly acidic to neutral with low cation exchange capacity (CEC) but moderate to high base saturation. Type of soil Natural Cohesion C Angle of Coeff. of void ratio (kg/cm2) internal friction permeability Sub-soil investigations carried out at different locations of severely erosion affected Majuli (Degree) (cm/sec) island by the River Research Station extending up to a depth of 30 m indicate that the island is mostly underlain by gray coloured, fine to medium size, poorly graded sand (SP-type) CI 0.73 to 0.78 0.25 to 0.28 6.5 to 80 (0.044 x 10-4) covered by light gray coloured silt mixed with clay and/or fine sand (CI and ML-type) of (0.74) (26.67) (70) varying thickness ranging from 1.5 to about 12 m. Pockets of soil rich in inorganic clay content ML 0.52 to 0.57 0.25 to 0.32 90 to 10 0 - (CH-type and CI-type) are also found in areas. (0.54) (0.27) (9.30) Physical properties of flood plain soils (Majuli Island) SP 0.47 to 0.57 0 240 to 280 (17.0 x 10-4) Type of Specific Grain size distribution (0.49) (26.40) soil gravity CH 0.75 to 0.78 0.28 to 0.34 7 0 - Clay (%) Silt (%) Sand (%) Gravel (%) (0.77) (0.31 (70) CI 2.59 to 2.67 4 to 22 65 to 83 10 to 28 - Source: R.R. Station, WRD (1996) (2.62) (6.7) (73.3) (20.0) Values within the parentheses indicate averages. ML 2.68 1.0 27.0 72.0 - The engineering properties of the bank material deposits with typical example of Palasbari- SP 2.61 to 2.70 0 to 3 2 to 17.5 82.5 to 98 - Gumi reach just down stream of the Guwahati city shows that the top soil of about 5.0m thick (2.68) (1.67) (15.34) (86.08) consists of silty clay deposit underlain by coarse to fine-grained silty sand deposits of more CH 2.64 22 68 10 - than 30.0m thickness. The different soil properties vary widely as the depth increases.

47 48 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Figure 5: 5 km long erosional svarp at Rohmoria Figure 3: Typical bank material in Palasbari

Figure 4: Erosional scarp of Rohmoria showing loose sand layer at bottom Figure 6: Bank erosion at Hatisal area in Jorhat District

49 50 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Management Measures Adopted : The flood and erosion management measures started in Assam after the declaration of National Flood policy in 1954. Accordingly, a huge network of flood embankments were erected all over the state of Assam in the main stem river Brahmaputra, Barak and its tributaries as immediate & short-term measures under the "food for work" programme. The development of flood embankment infrastructure in Assam is shown in figure 9.

Figure 7: Bank erosion in Neamatighat in Jorhat District

Figure 9: Development of embankments and town Figure 8: Bank erosion in Sonarigaon in Morigaon district protection /anti-erosion work in Assam

51 52 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

The short & medium term measures taken up under the policy initiatives also include anti With the emergence of geo-textile technology, the department has started adopting the erosion and river training works that mostly comprise of bank revetments, construction of technology at many selected reaches. At Matmara area, it has extensively used the geotextile stone spurs, boulder deflectors, timber dampeners, pile screens R.C.C. porcupines, Leet technology in the form of Geo-tubes and geotextile scour aprons tubes, which is the first of its Fencing & other Pro-Siltation Devices. In addition to above, the W. R. Department also kind in India. No such attempt has been made for river bank erosion protection in India. constructed 86 numbers of major sluices, 539 numbers of medium & minor sluices and about 855 km of drainage channels to provide adequate country side drainage and dewatering facilities. The emergency situations arising in flood seasons were mostly taken care of by some temporary measures like providing dowel bund with empty cement bags, back filling with bamboo pallisading, A-Type spurs, bamboo porcupines, breach closing works, bamboo cribs etc. All the above measures have provided reasonable protection to about 16.50 Lakh hectare (50%) of area out of total flood prone area of the state 31.20 Lakh hectare as assessed by the "Rastriya Barh Ayog", Govt. of India. Extensive riverbank protection or anti-erosion work was started only after the flood protection embankments became more and more vulnerable to breaches from erosion. About 70% of the total present day embankment system of the state was built from the mid-1950s until the end of the 1970s with a large setback distance away from the riverbank, up to two kilometers. Due to consequent widening of the river, the embankment system also becomes vulnerable at many reaches and as a result, adequate flood protection was lost. Since then, more Tubular Sand Filled Geotextile Mattress used for bank pitching work at river Pagladia emphasis was laid on building anti-erosion/bank protection works commencing about 20 years after embankment construction (Error! Reference source not found.. 9). Wherever the embankments are away from the riverbank, they are mostly functioning well along the Brahmaputra - provided they are not eroded. The comparison of embankment failures during the high 2004 flood indicates that more than 50% of the embankments along the Brahmaputra failed from erosion. Since 1970, the Water Resources Department is using different kinds of Technologies for protecting riverbank and river training works. In last few decades, it has extensively used chiseled and blasted boulder as one of the chief material for anti erosion and river training works. Although, it is not very cost effective, material has been found to be very effective in these works.

Geo Tubes and Geo Matress used as scour apron at Matmara for bank protection In the last decade the Water Resources Department has been extensively using RCC porcupines as pro-silting devices. The experience gained with the technology has been very helpful in protecting some of the very actively eroding banks and reclaiming land as well as training of the rivers.

Extensive use of bouldes for construction of apron and land spars for river training.

53 54 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

where embankments were retired up to 10 times, without providing reliable bank protection. A direct comparison with the former town of Palasbari, the area of which was protected from erosion 30 years later after the town had been eroded, reveals a comparable level of cost for structural work with the difference of substantial land losses and the erosion of the town. The comparison of these two examples supports that "riverbank protection first" can be a feasible, long-term approach despite the higher initial investment cost, especially in more intensively used areas. This opinion has been more and more adopted by different government committees on floods. Over time, riverbank erosion is gradually acknowledged as major problem with justification not only for town protection but also alongside important agriculturally used areas. However, it is understood that the approach of "erosion protection first" has only a chance for large-scale success, if based on more cost effective technologies, drawing on international best practice. Till now, due to lack of resources, a piece-meal approach was adopted to deal with the The porcupine bars laid for chocking of channels in river Manas and Brahamptra. riverbank erosion problem in response to emergency situations depending on when and where funds are available. A holistic approach or a long-term strategy based on a systematic understanding of the problem is very much essential before seeking the engineering solutions to the problem. References: Sarma, J. N. (2005) "Fluvial process and morphology of the Brahmaputra River in Assam, India" Geomorphology, Elsevier, Vol. 70, issue 3-4, PP 226-256. WRD (2008) "North Eastern Integrated Flood and RiverBank Erosion Management Project: Feasibility Study (PPTA, Phase II)" Unpublished report of Water Resources Department, November 2008.

n n n

Siltation observed after the installation of porcupines The population density in the flood plains indicates the need for sufficient and adequate flood & erosion management (structural - non-structural) works. There are numerous towns and urban centers all along the Brahmaputra River whose existence today can't be imagined in absence of the existing town protection works. Dibrugarh town in upper Assam is a glaring example and tells a major success story in riverbank protection in Assam. The town was on the verge of extinction due to severe erosion after the devastating flood of 1954, a consequence of the 1950 earthquake. Following this, Dibrugarh Town Protection Work was taken up and it was protected from extreme erosion in the mid-1950s. Following the completion of riverbank protection work, the flood embankments were erected and the town was protected from flooding. The work performs until today, allowing the town to develop and prosper at the same location since 50 years. This stands in sharp contrast to many other areas in Assam

55 56 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

1 in 8 or in some cases 1 in 6. Hydraulic Gradient line should be determined on the basis of GEO ubeT Embankments-Challenges the analysis of the soils, which are to be used in the construction of embankments. However, the following guidelines are recommended. Before the Engineers-A Case tudyS Type of fill Hydraulic Gradient Clayey Soil 1 in 4 Er. Nayanjyoti Goswami Clayey sand 1 in 5 Assistant Engineer Sandy Soil 1 in 6 Water Resources Department Hydraulic gradient line plays a significant role in fixing the shape of the embankment section as it determines the seepage profile of flood water within the embankment section. Flatter the ABSTRACT hydraulic gradient line, wider will be the seat of the dyke as the H.G. Line has to be covered at Flood control activities were initiated in Assam by the Flood Control Department (later any cost to prevent seepage of water during the high spate of the river. But, unfortunately, renamed as water Resources Department) after announcement of National Policy on Flood people in the riverine areas tend to settle on the embankment during flood season along with during the year 1954 with immediate construction of earthen embankments along the river the livestock to get relief of flood water. This obviously damages the embankment section and banks. The embankments were constructed mostly using locally available soil, which is sandy in combination with natural wear & tear, the dyke section is further deteriorated. The H.G. Line in nature. The department has so far constructed about 4473 Km of embankments along the of a dilapidated dyke is easily exposed in the country side slope, which ultimately lead to failure banks of river Brahmaputra, Barak and other tributaries. However, due to nature of the soil of the embankment in the form of breach. This problem of embankment failure is very common in the state, which can be get rid of by either preventing the dyke from getting damaged by and meandering behaviour of the rivers, mainly north bank tributaries, embankments breached human / cattle or by replacing the conventional method of construction of embankment by time to time thereby leading to miseries of the people. Finally, the department considered for some other technique, which is not readily damaged by external factors. taking up one pilot project of constructing embankments using innovative geo-tubes for the first time in the country. The project was executed during the year 2009 - 2011 along the bank Background and concept for taking up geo-tube technology for embankment of river Brahmaputra from Sissikalghar to Tekeliphuta in Dhakuakhana area for a length of construction 5.00 Km, which is still standing well and functioning as anticipated. The Water Resources Department took up the concept of using geo-textile materials for construction of the breached portion of the Sissikalghar-Tekeliphuta dyke in Lakhimpur district The Water Resources Department - a glance of Assam. The Brahmaputra dyke from Sissikalghar to Tekeliphuta was constructed during The Water Resources Department (originally called the Flood Control Department) the year 1955-56 for a length of 27.125Km at about 3 km away from the river. The dyke was performed works under the name Public Works Department (PWD) till the year 1970, after breached for the first time by erosion at its 17th km in 1964 and also a number of times by which the department along with the Irrigation Department bifurcated from the parent flood & erosion in few subsequent years, followed by subsequent plugging by construction of department i.e. PWD. Again in the year 1974 the Irrigation Department was separated out retirements, out of which the breaches in 2005 upto 2008 were consecutive at 19th to 23rd from the then Flood Control Department Subsequently, the department was renamed as Water Km near Matmara area. The breach in 2008 was more than 3 km wide and flood water from Resources Department in the year 2002. Various flood control activities in Assam started after the mighty Brahmaputra entered the country side areas, devastated about 10,000 hactre in announcement of National Policy for Flood in 1954 by the Government of India. Though there the immediate vicinity and about 41,000 hactre at far down stream areas, affected a population was short term and long term measures in National Flood Policy of 1954, to get the immediate of about 2.5 lakh in about 20 villages and deposited huge silt in the greater Matmara areas. relief to the flood ravaged state, construction of embankments as short term measures had The breach closing works were executed at a safer distance from the river and thus during been widely adopted because this could be constructed quickly with local resources and the period from 2005 to 2008, a handsome area of land was lost. Subsequently, the department abundant manpower to protect large area. came up with the complete new innovative proposal for construction of embankment by using geo-textile materials. The proposal was discussed by several experts including professor of However, for construction of embankments, locally available soil has been used in all the IIT, Guwahati and other higher official of the W.R. Department, which concluded to construct cases in the state to give flood relief during high spate of the rivers. Soils available in the the retirement at 500 m minimum margin with sand filled Geo-tubes as construction material, upper reaches of the river Brahmaputra comprises mainly of coarse sandy soil. This alluvial as (1) the earthen embankment as high as 7 metre may not remain in shape and get severely sandy soil is highly susceptible to erosion, which is one of the major causes of breaches to damaged by raincuts, (2) construction will be speedy by pumping the geo- tubes with sand- the embankments during the flood season. Further, because of the nature of the soil, the slurry. The construction of embankment with Geo Tubes is an internationally proven technology Hydraulic Gradient (H.G.) line inside the embankment section is very flat to the tune of about especially where time for construction is limited and god quality soil cannot be availed locally. 57 58 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

As there was limited time for completion of the breach closure work before the onset of flood June'2009, delay in custom clearance for bringing the materials at Calcutta Port, Road Permit of June, 2009, the department decided to use the geo tube technology in construction of the for carrying materials from Buxirhat to work site besides some local problem etc. Even then, retirement. the laying of geo-tubes in the retirement was completed during the first week of March'2010. For construction of the dyke by using Geo-textile tube (Mega- containers), geo-tube with Finally, the work was completed in all respect by December'2010. fill height of 2.5m, Tensile strength of more than 200 KN/m and UV Resistance (ASTMD 4355-500 Hrs) more than 80% have been used. Finally, the project under nomenclature "Raising & strengthening to Brahmaputra dyke from Sissikalghar to Tekeliphuta including closing of breach by retirement and anti-erosion measures (to protect Majuli and Dhakuakhana areas against flood devastation by the Brahmaputra)" amounting to Rs.140.98 Crore with the following provisions had been framed up by the department with the following major provisions:- i) Construction of the breach closing retirement for a length of 5000 m with Geo-tube in the core (1 over 2 over 3) and covered with earth in embankment section of 6 m crest & 3:1 side slopes. The size of the geo-tubes were 25 m long with fill height of 2.50 m. The apron of the embankments were proposed to be protected with apron tube of 16m and 12m length and further the river side slope was proposed to be turfed with geo-textile mattress filled with sand. ii) Raising & Strengthening of the existing dyke at upstream and downstream for a length of 13,905 m. iii) Anti-Erosion measures with RCC porcupine screens. The main problem in executing such a major scheme was the provision of fund. However, the scheme was sanctioned by the Ministry of Water Resources, Govt. of India for execution under Flood Management Programme during January'09. The work for construction of the 5 Km long geo-tube dyke was then awarded to a Malaysian company during March'09 at the cost of Rs. 99.97 Crore with target date of completion as 100 days from the date of signing of Tender Agreement. The work of installation of geo-tubes at site was started from the first week of June'09. But the work could not be completed in the stipulated time due to various reasons some of which were beyond control such as sudden rise of water level on 30th

Photographs showing laying of geo-tubes and completed section

Conclusion : Although the project comprising construction of retirement dyke may be termed as pilot project, being the first of its kind in the country, the structure has successfully been able to withstand the consecutive floods of 2010, 2011 and 2012. This successful project can be followed as guidance for designing flood embankments in other parts of the state also. No doubt, that the initial cost of the project per Km is on the higher side compared to the conventional method, even then it will cost less in the long run considering the high benefits yielded in the form of saving agricultural land, private & public properties etc. The method may be adopted in phased manner to cover all the major flood prone areas of the state, which will certainly boost the economy of the state. n 59 60 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Operational Flood Early Warning System (FLEWS) - A eospag tial and ydrh o-met approach as developed yb NESAC for Government of Assam

Diganta Barman, S.S Kundu, Jonali Goswami, Ranjit Das, NGR Singh, Arup Borgohain, Rekha Bharali Gogoi, Victor Saikhom, Suranjana B Bora, S. Sudhakar North Eastern Space Applications Centre (NESAC) Government of India, Department of Space Umiam, Shillong, Meghalaya-793103 Fig 1: Satellite image covering all three study areas Major objectives:

Introduction: The study has been taken up to achieve following short and long term objectives Flood is a chronic disaster occurring almost every year in the state of Assam. Along with (1) Issue of alert for possible flood situation in District/ Revenue Circle/ Village level with best structural measures like the construction of embankment etc, non structural measures like possible lead time. (Operational). flood forecasting, flood plain zonation and regulation etc in recent past has gained importance among researchers, technocrats and policy makers. In this context an attempt has been (2) Submission of annual periodic report on post-flood status of existing embankments in made by North Eastern Space Applications Centre (NESAC) under Department of Space, district level (Operational). Government of India at Shillong, Meghalaya to mitigate the flood damage by developing an (3) Development of optimum methodology for rainfall prediction from satellite based weather operational flood warning system for the state of Assam by judiciously using the strength of monitoring and numerical weather prediction models supported by insitu ground data geospatial technology coupled with established relationships among important hydro- (Research) meteorological parameters. (4) Development of river specific rainfall-runoff models for forecasting of flood (Research) Study area: The catchment areas of the major known flood causing rivers whose flood plains lies in (5) Development of inundation simulation for flood plain zonation (Research) the districts of Lakhimpur, Dhemaji (Upper Assam) // Nalbari, Barpeta & Baksa (Lower Assam) // Cachar, Karimganj & Hailakandi (Barak Valley) in Assam.

61 62 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Methodology: (2) The meteorology component: This component of the FLEWS workflow basically deals with two sub-components viz Keeping in view the above mentioned objectives, following methodology has been adopted. Near real time weather watch with daily collection insitu rainfall reading from various sources like Automatic Weather Stations, Automatic Rain Gauges etc and Running of Numerical weather prediction model such as Weather Research Forecast (WRF) for forecast of 3 hourly rainfall forecasts in grids of various spatial resolution such as 27 km * 27 km , 9 km * 9 km, 3 km * 3 km etc. that goes as the daily input to the run-off model.

Fig 2: Flow chart combining geospatial technology hydro-met components Operational work components: In conjunction with above methodology, following components are briefly discussed below (1) Embankment and Breach monitoring from high resolution satellite data: This component of FLEWS deals with analysis of high resolution satellite data on an annual basis after the completion of flood season in order to identify existing breaches in various embankments created during the completed flood season and to be reported to the concerned Fig 4: Rainfall forecast generated by WRF model over upper Assam authority/ department to enable them to take corrective actions for the next season. (3) The Hydrology Component: This component of the FLEWS workflow basically deals with two sub-components viz preparation of all hydrology specific watershed layers such as basin boundary, landuse, drainage, slope, aspects, soil classification etc leading to calculation of various watershed parameters such as Time of Concentration, Co-efficient of discharge etc. and generation of discharge forecast with two approaches by using a lumped and a distributed hydrological model. Here the lumped approach delivers the peak discharge forecast and the distributed approach delivers a daily hydrograph with single or multiple peaks. The output of both the models together finally leads to the decision to issue a flood alert on the concerned river and the district.

Fig 3: An embankment breach identified on CARTO-I ortho-rectified data

63 64 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Conclusion: This project been taken up on the joint request of Assam State Disaster Management Authority (ASDMA) under Government of Assam and the North Eastern Council (NEC), Ministry of DONER, Government of India. Based on the initial success achieved so far, fresh request has come from Government of Assam for implementing this project in all the flood prone districts of Assam in phases. Under this project all major stake holder agencies such as IMD, CWC, Assam Water Resources Department (AWRD), Brahmaputra Board etc have been brought under a common umbrella of joint participation and accountability in the endeavor for effective management of flood in Assam. Moreover important issues such as river bank erosion, scientifically selected locations of hydro-met observation stations and equipment/ sensor modernization, effective communication and alert dissemination system etc which were seldom discussed earlier has come up for serious discussions in recent times as part of this project. At the behest of NDMA, New Delhi states like Bihar and West Bengal has also officially corresponded to NESAC for exploring avenues for joint collaboration for their respective states. Due to the gradually improving performance of FLEWS, in 2012 this project has been Fig 5: HEC-HMS distributed model set-up for a river basin in upper Assam selected for Professional documentation under “Good governance initiative” by Department Results: of Administrative Reforms & Public Grievances under Ministry of Personnel, Public Grievances & Pensions, Govt. of India. Thus the FLEWS project has been able to start a new holistic Based on the above described operational work components, flood warnings has been approach to look at the overall disaster management scenario in North Eastern Region of issued to concerned district authorities several times during 2010 and 2011 monsoon seasons India. in Assam with an average lead time of 12 to 18 hours. Majority of the significant flood events during these two years has been successfully forecasted and encouraging feedbacks have been received from the user. n n n

Fig 6: Testimonial of forecasted flood in Lakhimpur district on 13th and 14th July, 2011

65 66 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

discharge of domestic sewage and industrial effluents are the distinctive character of both industrial and urban activities. Therefore, the rivers, lakes and other water resources were affected by the above causes in respect of the morphological and ecological aspects. Statement of the Problem The Study of aWter Uses Based onater W The water of the Brahmaputra River is being gradually affected due to urban and industrial activities in Assam. The Brahmaputra River is one of the most important river in the world with about 2900km in length. The river is generally known as Tsangpo in Tibet, Siang or Quality ofhe t River Brahmaputra, Assam Dehang in Arunachal Pradesh, Brahmaputra in Assam and Jamuna in Bangladesh. Earlier, the water of the Brahmaputra River had been used for various domestic purposes such as drinking, bathing, cleaning and other aesthetic purposes without treatment. Now, the water of this river cannot be used for any domestic purposes without treatment in order to increasing Dhwajendra Nath Das organic pollutional load. Therefore, the use of water is being restricted for various purposes. Senior Environmental Engineer Pollution Control Board, Assam Water Quality Objectives The water quality objectives of freshwaters take into account various uses to which water ABSTRACT is put such as irrigation, drinking, industry, power generation , recreation and even for discharging waste waters together with the fact that all water bodies or water resources are The water quality is most important for various uses water such as irrigation, drinking, not necessarily required the quality to meet all potential uses. Therefore, this has led to the industry, power generation, recreation and disposal of waste water. Water uses of surface concept of classification and zoning of water bodies which indicate that their quality has to water is being gradually constrained due to increasing pollution load. The water quality of the meet the requirement of one or more for various potential uses. The water quality criteria has Brahmaputra River is being gradually deteriorated in order to receiving of effluent, waste been established for each typical use and it reveal to take into account the special constraints water and other waste material from various sources. The water of the Brahmaputra River on water quality imposed by the particular use. Based on this, any water resources or water cannot be used for any domestic purposes without treatment due to increasing pollution load. bodies can be designated for some particular best use which can be termed as "Designated Deterioration of water quality is evaluated by the BOD, DO%, CPCB and ISI Classification best use". As a result, the Central Pollution Control Board along with State Pollution Control along with NSFWQI which indicate to use of water for various purposes. Boards has adopted a scheme of classification and zoning of water bodies for designated Key Words best use of water for various purposes. Water quality, Biochemical oxygen demand, Percentage saturation of dissolved oxygen, Review of Literature Status of water quality, Water quality index. The environmental issues dominated after the Stockholm Conference in 1972 which led Introduction to growing realization of the problem of water pollution and resulting in a rapid proliferation of hydrobiological studies. Rivers are being studied for last several decades by various The industrial and urban activities is a simultaneous modern techno-economical fashion departments along with scholars and researchers of different disciplines. Besides, various in all around the world and finally initiated to adverse impact on the neighbouring water conference was held to draw the attention of the Central and State Governments and resources. The growing population and subsequent industrialization and urbanization are particularly of the public toward the deteriorating condition of the rivers and other water bodies. the main unabated polluting causes of rivers in the world. Therefore, the growth of literature and data, based on water pollution with special reference The urban areas occupy roughly 0.3% of world's geographical area and accommodate to industrialization and urbanization was influenced after implementation of the Ganga Action about 40% of the world's population. About 27% of the Indian population are living in urban Plan, 1985. areas which will increase upto 50% by 2015. Therefore, Indian urban population makes up The growth of population and subsequently industrialization and urbanization are one of the largest country in the world. The dynamics of industrialization and urbanization unabatedly polluting the rivers. The quality of river water starting from the source to the sea is along with increase of population has led to the growth of large modern urban complexes. a mirror of human activities. Water has been drawn for various used such as drinking, washing, High density of population, high consumption of energy, large amount of solid waste generation, bathing, industries, agriculture, and other purposes and return to the river at downstream as

67 68 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 effluent and municipal waste water along the flow path. As a result, the fresh water is becoming These sources discharges their effluent and waste water into the neighbouring area and an increasing scarce resources due to industrial, urban and anthropogenic activities. As finally goes into the mighty river Brahmaputra. population and development pressure continue to grow, most of our water bodies have become Methodology polluted (Saluja and Jain, 1998) [14]. Murugesan and Sukumaran (1999) noted that rapid population growth, increasing living standard, wide sphere of human activities, growing The study incorporates relevant data collected from various secondary sources but mainly industrialization and urbanization have resulted in greater demand of good quality water, depend upon the primary data generated from the water quality analysis. The water samples while on the other hand, pollution of water resources is also increasing steadily in the future were collected on monthly basis taking proper care in selection of the sampling stations. days [10]. Sampling Stations (SS) India have 113 river basins out of which 14 are major, 44 medium and remaining 55 are Ten (10) sampling stations were selected after reconnaissance survey of the river. Samples minor rivers [6]. The 14 major river basins accounts for 83% of the total area of the basins were collected on monthly basis and analysed for necessary parameters. Sampling stations and hence contribute 85% of the total surface flow and cover about 80% of the total length are tabulated in the Table-1. (Chaudhuri, 1983) [4]. Table-1 : Sampling stations of the Brahmaputra river Marine organisms are gradually decreased by 40% during the last two decades. Considering to human health, number of diseases affecting heart, kidney, nervous system Sl. SS Locations Sources of Pollution before SS and bones are caused owing to pollution of the aquatic environment. Nearly, 20 lakhs people No are dying annually on account of polluted water in India. The polluted water takes the life of 1 SS Balijan Waste water, coal & lime mining, oil drilling & erosion one child in every minute in India. 1 2 SS Maijan Waste water, coal & lime mining, oil drilling & erosion The Central Pollution Control Board has indicated that mean BOD values have gone up in 2 3 SS Nimatighat Waste water, coal & lime mining, oil drilling, refinery, fertilizer, all major rivers during the last two decades. The Board also mentioned that Kerela at the 3 bottom and Maharashtra at the top in respect of such BOD value. The states such as Assam, petrochemicals & erosion Uttar Pradesh, Gujarat and Tamilnadu are most affected in respect of coliform bacteriological 4 SS4 Dhenukhana Pahar Waste water, coal & lime mining, oil drilling, refinery, other pollution. Gujarat ranks first followed by Maharashtra, Andhra Pradesh, Tamilnadu, Uttar industrial operation and erosion Pradesh and Punjab in respect of Chemical Pollution. Recent survey has revealed that almost 5 SS Chandrapur Waste water, coal & lime mining, paper mill & erosion all major rivers in India have become highly polluted (Mahajan, 1988) [7]. 5 6 SS Kacharighat Waste water, urban run-off and other industries & erosion The World Health Organization (WHO, 1985) had found that more than 1000 organic 6 chemicals are present in river water and effluent [16]. Receiving of such effluents has great 7 SS7 Pandu Waste water ashes of crematoria, industrial operation, religious impact on the physico-chemical and biological character of the river system. The gradual purposes, refinery and other human activities increase of physico-chemical parameters might have caused elimination of all indigenous 8 SS Sualkuchi Waste water and industries & erosion life leading to the formation of biological desert (Rana and Palria, 1982) [12]. 8 9 SS Jogighopa Waste water, industries, coal mining and erosion Souces of Pollution 9 10 SS Dhuburi Waste water, refinery & other industries and erosion The following sources impaired the water quality of the Brahmaputra River as; 10 SS : Sampling Station 1. Oil drilling 9. Agriculture run-off 2. Coal and lime mining 10. Transportation Experimental Works 3. Refining operation 11. Open defaecation Physico-chemical and bacteriological parameters were evaluated by the methods and 4. Paper industry 12. Ashes of cermetation techniques are specified in Standard Methods for the Examination of water and waste Water 5. Thermal power plants [APHA-AWWA-WPCF-1995]. 6. Fertilizers industry 13. Waste of religious purposes Water Quality Analysis 7. Domestic waste water 14. Erosion 8. Urban run-off 15. Other human activities Indiscriminate disposal of effluent, waste water and sewages in rivers has led to serious 69 70 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 river pollution in India. Therefore, effective monitoring of parameters is an important initial Results and Discussion step in abutment of river pollution. The water quality of the Brahmaputra River has been The water of the Brahmaputra River has been monitored for physico-chemical parameters monitored for the physico-chemical parameters such as physical, chemical and bacteriological such as physical, organic, mineral, other inorganic and bacteriological such as total coliform parameters. and faecal coliform. These parameters are very important for ascertaining the water quality of the river system. The status of water quality and water quality index has been evaluated based on experimental data to ascertain the exact water quality all along the mighty river Brahmaputra for various uses. Status of Water Quality The water quality of the Brahmaputra River has been ascertained by the Percentage Saturation of Dissolved Oxygen (DO%), Biochemical Oxygen Demand (BOD), Central Pollution Control Board and Indian Standards Institution Classification of water resources. Biochemical oxygen demand The BOD can be used as an indicator of river pollution to ascertain water quality of river pollution. The UK Environmental Agency has established a system of classification on the basis of BOD value to ascertain the water quality in the following Table-2 of the water resources. Table-2 : Surface water classification by BOD level

mg Sl. No. BOD ( /l) Classification / Status of Pollution 1 1.00 Very Clean (VC) 2 2.00 Clean (Cl) 3 3.00 Fairly Clean (FC) 4 5.00 Doubtful (Do) 5 10.00 Bad (Ba)

The BOD value of the Indian rivers are normally high with compare to the western countries due to human and animal bathing, idol immersion, praying and devotion, mass bathing in religious occasions, open faeces, discharge of industrial effluents and untreated waste water, mixing of ash from crematoria, throw of carcassial matter, agriculture and urban run-off and other human activities. Therefore, the CPCB and ISI has fixed the BOD value 2mg/l for Class-A water for designated best use of water sources. The water quality of the Brahmaputra River at the various sampling stations has been ascertained on the basis of BOD value and tabulated in the Table-3 as shown below;

71 72 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Sl. No. SS BOD (mg/ ) SOP The content of DO at various sampling stations are tabulated against the pollutional status l of the Brahmaputra River in the following Table-5 as; 1 SS1 2.60 FC Sl. No. SS DO% SOP 2 SS2 2.10 FC

1 SS1 84.10 NOSP 3 SS3 1.50 Cl 2 SS 86.34 NOSP 4 SS4 2.10 FC 2 5 SS 1.90 Cl 5 3 SS3 85.38 NOSP 6 SS 1.70 Cl 6 4 SS4 87.62 NOSP

7 SS7 1.50 Cl 5 SS5 86.91 NOSP 8 SS8 1.10 Cl 6 SS6 88.71 NOSP 9 SS9 2.30 FC 7 SS7 86.73 NOSP 10 SS10 1.60 Cl 8 SS 86.64 NOSP Table-3 : Status of pollution in the Brahmaputra river by BOD 8 9 SS 88.89 NOSP SOP : Status of Pollution 9 10 SS 88.56 NOSP The BOD represents intensity of biodegradable organic matters remaining in the stream 10 at any time and thus indicates the amount of molecular oxygen required by bacteria to reduce the carbonaceous material. The BOD value is high at the upstream of the river and gradually Table-5 : Status of pollution of the Brahmaputra river by DO% decreases upto SS8 due to dilution of the river water. The BOD value is also increased at No or Slight Pollution of Water (NOSP) SS9 because of human activities. The BOD range of 1.10-2.60 is found all along the Brahmaputra River in the study period, 2011. The water of the Brahmaputra River is under the No or Slight Pollution of water. The water is clear, fresh and odour free, pollution sensitive species and fish are present in the river Percentage Saturation of Dissolved Oxygen (DO%) water. The dissolved oxygen is a good indicator for the status of pollution of a surface water body in terms of its chemical and biological pollutants. The rate of de-oxygenation reflects the CPCB and ISI Classification BOD exertion rate and the re-aeration rate is also directly proporational to the DO deficit from Parameters for primary quality criteria for various uses of inland or surface water has the saturation value. As such, the dissolved oxygen is used as a good indicator to ascertain been prescribed by the CPCB and ISI, 1982. The CPCB classified the water sources in the the pollution level in the river water. In view of this, the surface waters are classified in the following Table-6 as; following Table-4 on the basis of percentage saturation of DO level as; Sl. No. DO% SOP Significance Sl. No. Designated best use Class of Water 1 0-5 Extremely Sever Highly turbid; dark gray to black colour; bad eggs smell; 1 Drinking water source without conventional treatment but Class-A Pollution (ESP) emit H2S, MH3 & CO2, and fish absent after disinfection 2 6-10 Sever Pollution (SP) Gray colour with rotten smell and fish absent 2 Outdoor bathing (Organized) Class-B 3 11-70 Moderate Pollution (MP) Transparent or slight turbid, uncoloured, odour free and 3 Drinking water source with conventional Class-C fish present treatment followed by disinfection 4 71-90 No or Slight Pollution (NOSP) Clear, fresh & odour free and fish present 4 Propagation of wildlife & fisheries Class-D 5 91-100 Clean (Cl) Very clean water and most pollution sensitive species are 5 Irrigation, industrial cooling & controlled waste disposal Class-E present Table-6 : Classification of water bodies by CPCB, 1979 Table-4 : Surface water classification by DO% level

73 74 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

There should be no visible discharge of domestic and industrial waste waters into the Good quality of water Class-A water. Any discharge shall be regulated and treated as to ensure maintenance of the This type of water has been found within sampling stations SS1-SS6 and SS10 due to stream standards in case of Class-B and Class-C water. The Brahmaputra River is receiving dilution in the river system. effluents and waste waters from various cities and industrial sources. Besides, the river water have contain the total coliform, faecal coliform and faecal streptococci. Therefore, the water Medium quality of water of the Brahmaputra River is considered as Class-C water inspite of the physico-chemical The medium quality of water was found within sampling stations SS7-SS9 due to confluence parameters are below the permissible limit as prescribed by the CPCB and ISI standards for of untreated domestic waste water and treated effluents and other human activities of the classification of inland surface waters. river bank area. Water Quality Index The water quality index is most important to ascertain the quality of surface water in regard Conclusions of pollution status. The water quality index is a mathematical aggregation of two or more The following important conclusions can be made from the study; indicators in some fashion and simply a numerical value having no unit and reflects some 1. The water quality of the Brahmaputra is found within Fairly Clean and Clean Water as environmental attributes. per the BOD Classification. Brown et al. (1970) had presented a water quality index similar in structure to Horton's index. It is called the National Sanitation Foundation Water Quality Index (NSFWQI). A 2. The water quality of the Brahmaputra River is under No or Slight Pollution of water as per decreasing scale 100-0 is used for expressing the water quality index and index values are DO% Classification. related to 5 descriptor words and colours is shown in the following Table-7 as; 3. The water quality of the Brahmaputra River is under Class-C category as per the CPCB Sl. No. Descriptor Words Numerical Range Colour and ISI Classification. 1 Very Bad 0-25 Red 4. The NSFWQI indicates that the water quality of the Brahmaputra is normally Good quality 2 Bad 26-50 Orange water within SS1-SS6 and Medium quality in between SS7-SS9 and Good quality of 3 Medium 51-70 Yellow water at SS10. 4 Good 71-90 Green 5. The water of the Brahmaputra River can be used as drinking water source with conventional treatment followed by disinfection. 5 Excellent 91-100 Blue Table-7 : Descriptor words and colours for reporting NSFWQI 6. The water of the river can also be used as Class-D and Class-E water. The water quality index of the Brahmaputra River at all sampling stations were calculated 7. The Brahmaputra River has high self-purification capacity to reduce the pollution load in by NSFWQI. This water quality index is given in the following Table-8 to ascertain the water the river system. quality at the respective stations. Measures Sl. No. SS IV DW C The following measures are most important for the preservation of river water; 1 SS 71.32 G Gr 1 1. The industrial units have to discharge their treated effluents into the neighbouring area 2 SS 72.93 G Gr 2 under permissible limit. 3 SS3 72.77 G Gr

4 SS4 72.53 G Gr 2. The industrial units have to imply the zero discharge concept for the greater interest of

5 SS5 72.28 G Gr future generation. 6 SS 72.16 G Gr 6 3. The waste water treatment plant should be installed in all cities and town which discharges 7 SS 69.98 M Ye 7 their waste water into river Brahmaputra or other water bodies. 8 SS8 69.89 M Ye 4. The effluent of mining and drilling operation must be treated on most priority basis. 9 SS9 68.25 M Ye

10 SS10 70.43 G Gr 5. Open defeacation should be banned in the river bank area. Table-8 : Water quality index of the Brahmaputra river 6. Deposition of solid waste, ashes of crematoria, carcassial material, waste of religious IV : Index Value, DW : Descriptor Words, C : Colour, G : Good, M : Medium, Gr : Green, Ye : Yellow purposes and other human activities would be stopped for conservation of river water.

75 76 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

References 1. APHA - AWWA - WPCF (1995). "Standard Method for the Examination of Water and Waste Water", 19th Edition, Washing ton, D.C. 2. Central Pollution Control Board (2000). "The Brahmaputra Basin", Basin sub-basin inventory of water pollution, Ministry of Environment Forest, p. 31-39. Infiltration Studies inulsi K Pilot Basin 3. Champan, D. (1996). "Water Quality Assessments", 2nd Edition, Published by E & FN Spoon, London, UK . (Assam/Meghalaya) Under Different 4. Chaudhuri, N. (1982). Water and Air Quality Control, the Indian Context Central Board for prevention and Control of Water Pollution, New Delhi, India. Landuse and Soilypes T orf Efficient 5. Hydrology Project Training Module File, (2004). "Basic Aquatic Chemistry Concept" Version, 8/27/2004. Management of oundwGr ater orf Irrigation 6. Kumar, A. (2002). Ecology of Polluted Waters (Vol-I), 1st Edition, A.P.H. Publishing Corporation, New Delhi-2. 7. Mahajan, K.K. (1988). Deteriorating Nation's rivers. In : Ecology and Pollution of Indian Purpose Rivers. (Ed. Trivedy, R.K.), p. 1-38, Ashish Publishing House, New Delhi. S.R. Kumar S. Chakma 8. Mc Carty P.L., Sawyer C.N. and Parkin, G.F. (2003). "Chemistry for Environmental NIH, CFMS, Patna MNNIT, Allahabad Engineering and Science", Tata Mc Graw - Hill Publishing Company Ltd., New Delhi. 9. Met Calf & Eddy, Inc. (1995). "Waste Water Engineering Treatment, Disposal and Reuse" 3rd Edition, Tata Mc Graw - Hill Publishing Company Ltd, New Delhi. ABSTRACT 10. Murugesan, A.G. and Sukumaran, N. (1999). Impact of urbanization and industrialization Infiltration is considered as an important process in the management of water resources of the river Tamirabarani, the life line of Tirunelveli and Thoothukundi district, Proc. Sem- for crop production in both irrigated agriculture and dry-farming conditions. In irrigated Env. Prob. 1-6. agriculture, it is a fundamental prerequisite for designing, evaluating and managing irrigation 11. Peavy, H.S., Row, D.R. and Tchobanoglous, G. (1985). "Environmental Engineering" systems. Likewise, under dry-farming conditions, knowledge of infiltration is needed to model, International Edition, McGraw - Hill Publishing Company Ltd., New Delhi. evaluate and design management technologies to conserve soil and water resources. Precise 12. Rana, P.C. and Palria, S. (1982). Ecological studies of certain heavy metal pollution in design for irrigation water is required for higher irrigation efficiency, efficient use of water and Rajasthan, In : Proc. Nat. Seminar on minerals and Ecology (Ed. Banerji, S.P.), JSM, accurate prediction of the infiltration rate is of prime importance. In the present study field Dhanbad, India, VI-5, p. 1-4. infiltration tests were carried out using double ring cylinder infiltrometers under different soil- 13. Rendell, F. (1999). "Water and Waste Water Project Development", 1st Edition Published vegetation-landuse complexes in Kulsi Pilot Basin. Results were analyzed and typical infiltration by Thomas Telford Publishing, ISBN: 0727727117, London, E 144JD. rate and cumulative curves were developed. The results show large variation of infiltration 14. Saluja, D.S. and Jain, P. (1998). Physico-chemical analysis and Machna auniout dam rates depending upon various landuse and soil type conditions. The overall variation in the water with respect to its suitability for drinking and irrigation purposes. Poll. Res. 17(3) : steady infiltration rate for Kulsi Pilot Basin is found from 18.4 to 0.34 cm/hr. 219-221. Introduction 15. Statistical Hand Book Assam (2001-2011). Directorate of Economics and Statistics, Government of Assam, Guwahati-28. The sustainable development of groundwater resource requires precise quantitative assessment based on reasonably valid scientific principles. The assessment of groundwater 16. WHO (1985). Guidelines of Drinking Water Quality, Water Health Organization, Geneva- resource is a complex task which involves computation and estimation of different parameters 3 : 121. associated with the inflow and the outflow of this natural resource. In order to ascertain the n n n 77 78 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 groundwater resource in the shallow aquifers that gets annually recharged through rainfall Factors Affecting Infiltration and other sources under varied hydrogeological conditions in the country, scientific Availability of the moisture in the sub-surface soil depends mainly upon the number of methodology following well defined norms, need to be adopted. voids present in the soil, which, in turn, thus not depend upon the size of the soil particles but Groundwater is an important resource for meeting the water requirements for irrigation, rather upon the arrangement, sorting, shape and degree of compaction. Therefore, different domestic and industrial uses. Groundwater is annually replenishable resource but its availability soil will have different number of voids and hence the different capacities to absorb water. The maximum rate at which a soil in any given condition is capable of absorbing water is is non-uniform in space and time. Hence, the sustainable development of groundwater called its infiltration capacity. It is measured in cm/hr. The rate at which the water enters the resources warrants precise quantitative assessment based on reasonably valid scientific given soil at any given time is known as infiltration rate. It is also measured in cm/hr. Infiltration principles. National Water Policy, 2002 has also laid emphasis on periodic assessment of rates of soil decrease over time until a steady state is reached. In addition, the infiltration is groundwater resources on scientific basis. As 55% of water demand for agriculture and dependent on several factors, including soil texture, structure, initial soil water content, pore irrigation is met from groundwater, the development of shallow and deep aquifers play an size, soil metric potential and vegetation (Kumar et al. 1995). Management practices that important part for sustainability of tube wells (CGWB 2004). affect soil crusting and compaction, vegetative cover and soil porosity will increase or decrease Assam is one of the rich states of the country in term of the groundwater development the rate of water infiltration. For example, slow infiltration could be caused by increased soil potentiality. The entire Brahmaputra valley, covering more than 70% of the total geographical compaction. Increasing plowing depth significantly enhanced the final infiltration rate. The area of the state, contains prolific aquifer system with water table lying within 5 m of land most important factors that influence the infiltration rate are soil surface and its vegetation surface. cover (Chow et al. 1988). Some important factors affecting the infiltration rate are: The Annual Replenishable Groundwater Resource of the state has been assessed as Rainfall Intensity; Soil Texture; Vegetal Cover; 27.23 BCM and the Net Annual Groundwater Availability is 24.89 BCM. The Annual Entrapped Air; Effect of Water Quality; Effect of Forest; Groundwater Draft is 5.44 BCM and the Stage of Groundwater Development is 22%. The Agricultural Effect; Temperature of Water; Influence of Earthworms; recoverable recharge of groundwater in Assam is about 2 million hectare metre per year (CGWB, 2004). With the present groundwater resource available to be utilized, it is estimated Man's & Animal's Activities on the Ground etc. that an additional area of about 14 lakh hectare of net area sown can be brought under Water infiltration is rapid into large, continuous pores in the soil. It is reduced by anything irrigation. Besides the irrigational use, groundwater forms the most common form source of that decreases either the size or amount of pore space or moisture content, such as structure domestic use water in the state. From Fig. 1 and 2, it can be understood that groundwater breakdown, pore clogging by lodged particles, and the slower movement of deeper water as resources in Assam has immense scope for further development of dynamic resource. Thus, it reaches denser sub-soils. The value decreases with time due to filling up of larger pores, correct assessment and efficient management of groundwater resources becomes significant entrapped air unable to escape upward obstructed by presence of standing water, movement for a planned agricultural growth. of finer particles and clogging of pores and type of colloids. It also depends on landuse (Table 1). The rate is classified as very rapid to very slow as given in Table 2 (Chow, 1964). The infiltration process that is water entry into the soil affects the water budget in the watershed. Infiltration rates widely vary in different landuse and soil types under different Table 1 - Landuse and Infiltration Capacity (cm/hr) hydroclimatic environments. Infiltration characteristic of an area is of great importance for Textural Class Bare Landuse Vegetative Landuse hydrologic studies of the system. It is a basic parameter for water balance studies in an integrated crop, soil and water management plan. Infiltration affects the soil moisture status Loamy Sand 2.5 5.0 and is therefore amenable to vegetation manipulation. Determination of infiltration Loam 1.3 2.5 characteristics of a region is the basic necessity for its water management practices. Such Silt Loam 0.8 1.5 results have also vital applications in agriculture and hydrological modeling. Clay Loam 0.3 0.5 Infiltration is an important parameter in the hydrologic cycle and one of the thrust areas in hydrology, watershed management and irrigation water management. Infiltration is the only process by which precipitation enters the earth's surface and becomes potentially available to plant and animal life.

79 80 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Table 2 - Classification of Infiltration rates August. The temperature in the winter goes down to about 7 to 8 0C and in the month of July- August it shoots upto about 37 to 38 0C. In the uppermost reach, the temperature both in Classification Infiltration Rate Classification Infiltration Rate winter and summer is less than that of the lower reaches. (cm/hr) (cm/hr) Very rapid > 25.4 Moderate 2.0-6.3 Rapid 12.7-25.4 Moderately low 0.5-2.0 Moderately rapid 6.3-12.7 Slow 0.1-0.5 Very slow < 0.1 Objectives On Kulsi, at about 1.5 km downstream of Ukium village in Meghalaya, a dam site has been selected to generate hydropower along with a provision of irrigation and flood control. The entire river system is devoid of any water resources related developmental activities. The basin lacks adequate hydro meteorological and hydrological data which is a basic need for a hydro based project planning. Keeping in view the various existing gaps, field infiltration tests were conducted in Kulsi Pilot Basin. The study aims to find out: n The infiltration rate curves with respect to different land-use and soil types n The cumulative infiltration depth of water for different land-use and soil types Study Area The river Kulsi, also known as the Khri in its upper catchment in Meghalaya, is a South Fig. 1 : Status of groundwater potential of Assam with respect to other states bank tributary of the river Brahmaputra. The river originates from the northern slopes of the Khasi hill ranges, enters Assam at Ukium and after flowing through the plains of Kamrup District outflows into the Brahmaputra at Bahati near Nagarbera. The river has a total catchment of 1860 sq.km out of which about 1000 sq.km is in Khasi hills of Meghalaya and rest 860 sq. km in the plains of Assam. The whole basin area is bounded between longitude 9100' to 91045' and latitude 25030' to 26015' (Brahmaputra Board, 1988). The Kulsi River is composed of three rivers, namely Khri, Krishniya and Umsiri, all of which originate from West Khasi hill range and flows North and finally joins the Brahmaputra. The hill range is covered with evergreen forests and gets high rainfall during the monsoon. The Kulsi Pilot Basin can be divided into following three reaches: 1. The upper Khasi Hill reach 2. The middle reserve forest area reach and 3. The alluvial or flood plain reach. The climate of the basin, excluding the upper most reach, is similar to that of the other districts in Central Assam. The winter is cold and foggy, while the summer is oppressively hot and humid. The rainfall is substantially high during the monsoon. The annual average humidity Fig. 2 : Thrust on groundwater of Assam and other states for future irrigation requirement is 72% ranging from monthly average of 70% in the month of March & 85% in the month of 81 82 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Results and Analysis Concluding Remarks Based on field infiltration tests at 16 locations in Kulsi Pilot Basin, results were analyzed Infiltration is one of the processes for the recharge of groundwater and its knowledge is and infiltration curves for different landuse and soil types (as classified by USDA soil textural essential for proper management of water in all sectors. Infiltration is also one of the basic classification) have been developed. Results of field tests are summarized in Table-3 and parameter for developing an integrated crop, soil and water management practices and also Fig. 3 and 4. an integral part of the rainfall-runoff process whose modeling is required for planning and Representative values of steady infiltration rate with different land use and soil types under design of water resources systems. Efficient management of groundwater resource, using Kulsi Pilot Basin are summarised in Table-3, and it is found that steady infiltration rates with advanced methodology therefore assumes significance. respect to forest, shrub, agricultural, grassy and barren land use conditions with same soil Based on the infiltration tests in the Kulsi Pilot Basin, following conclusions can be derived type as silty loam are 12.3, 1.2, 0.8, 0.4 and 0.4 cm/hr; while teak forest with loamy sand and from the present study: grassy with silty soil are 9.2 & 0.72 cm/hr respectively. n Regional infiltration results are required to be developed for various river basins considering landuse, soil types and other factors. n While comparing the infiltration results with soil textures, information regarding grading of the soil is necessary to define better control of the soil types over infiltration characteristics. n By observing the large variation on infiltration results due to landuse effect it is necessary to report more infiltration results with landuse & soil types. n It is necessary to collect the information regarding different soil properties, water quality parameters, soil textures, landuse, climatic conditions, geological information from the test sites to define proper relationship of these parameters on infiltration results. References Brahmaputra Board (1988). "Preliminary Report on the Kulsi Multipurpose Project." Guwahati. Fig. 3 : Overall Variation in Observed Fig. 4 : Overall Variation in Observed Central Ground Water Board. (2004). Dynamic Ground Water Resources of India. Faridabad: Infiltration Rate Infiltration Cumulative Infiltration Ministry of Water Resources, Government of India. Testing location: site 1& 2 at Owguri, site 3at Bamunigaon, site 4 at Barbahar, site 5& 9 at Chow, V.T., (1964). Hand book of Applied Hydrology. Mc.Graw Hill Book Co. Andhari, site 6 at Ratanpur, site 7 at Maakeli, site 8 at Chaygaon, site 10 at Pachimdhuli, site 11at Rajapara, site 12 & 15 at Loharghat, site 13at Eri Chow, V.T., Maidment, D.R. and Mays, L.W. (1988). "Applied Hydrology." Mcgraw-Hill Tea Garden, site 14 at Barduar, site 16at Busko-Ashapara International Edition, New Delhi. Table 3 - Representative Steady Infiltration Rate under Different Land Use and Soil Types Kumar, S.R. et al. (1995). Infiltration Studies : Dudhnai Sub-Basin (Assam/Meghalaya). Case Study Report No. CS(AR)-183. NIH, Roorkee. Soil type Land use Representative Steady Infiltration Rate (cm/hr) Silty loam Forest 12.3 Loamy sand Teak forest 9.2 n n n Silty loam Shurb 1.2 Silty loam Agricultural 0.8 Silt Grassy 0.72 Silty loam Grassy 0.4 Silty loam Barren 0.4

83 84 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Applicability of groundwater for irrigation use depends upon the physical chemical & microbiological quality of water. The groundwater quality criteria for irrigation take into consideration effects of constituents or parameters of crops and other vegetation, soil, groundwater etc. The guideline for interpreting water quality can be used to identify potential problems in the use of the particular quality of water for crop irrigation. Poor quality water can Water Quality Indiceso Ensur t e the severely affect crop yields and damage soils. Various authors have depicted popular criteria to evaluate the quality of irrigation water (USDA, 1954; Ayers, 1977; Shainberge and Oster, Suitability of Groundwater orf Irrigation 1978; James, 1988). Accordingly, the quality of irrigation water could be evaluated on the basis of: n Toxicity hazards due to specific constituents and S.R. Kumar NIH, CFMS, Patna n Miscellaneous effects. ABSTRACT The important factor allied with the relation of crop growth to water quality is drainage. If a soil is open and well drained, crops may be grown on it with the application of generous Water is the next important input to fertilizer for crop production. If it is polluted, it may be amount of saline water, but on the other hand, a poorly drained area combined with application dangerous for plants, animals as well as for human being. Before using water for irrigation, its quality, which is equally important to its quantity, should be assessed so that it could not of good quality water may fail to produce satisfactory crop. For example, the application of create any health hazard. If low quality of water is utilized for irrigation, soluble salts and /or 100 mm of irrigation water containing 1000 ppm of salt to a hectare of land may introduce other toxic elements like arsenic may accumulate in the soil thus deteriorating soil properties one ton of salts in a poorly drained area. The reason is that the uptake of salts by plants is low and crop quality. In the paper, criteria available for evaluating the suitability of groundwater and continuous withdrawal of water by plants and evaporation leaves the salts in the soil for irrigation purpose like, electrical conductivity (EC), total dissolved salts (TDS), magnesium (Rhoades, 1982). hazard (MgH), sodium percent (SP), U.S. Salinity Laboratory classification, sodium adsorption Toxicity Hazards ratio (SAR), permeability index (PI), residual sodium carbonate (RSC), etc. are reviewed and discussed. Boron (B) is an essential minor element that is toxic to many crops if present in excess. Boron sensitivity varies from crop to crop. Traces of boron >0.5 ppm are injurious to citrus, Introduction nuts and deciduous fruits; cereals and cotton are moderately tolerant to boron; while alfalfa, As 55% of water demand for agriculture and irrigation is met from groundwater, the beet, asparagus and dates are quite tolerant (1-2 ppm). Boron toxicity guideline is given in assessment of regional water quality is important in determining the feasibility of water use Table 1 (www.spectrumanalytic.com). for the irrigation purposes. Good quality water helps maintaining agricultural productivity and sustaining soil fertility. Presence of few specific constituents beyond a limit in irrigation water may adversely affect the satisfactory growth of some field crops. Sodium, chloride, boron are the most common The suitability of groundwater for agricultural purposes is contingent to the presence of phytotoxins found in natural irrigation waters. Many other phytotoxins may be present in dissolved constituents in water. The long-term application of moderate quality water in poorly reclaimed sewage waters that are used for irrigation. Woody perennial plants are sensitive to drained land may accumulate high quantity of salts in agricultural land. The presence of salts sodium and chloride (tree fruits and grapes). Besides above mentioned elements, selenium, may harm plant growth physically by limiting the uptake of water through modification of osmotic processes, or chemically by metabolic reactions such as those caused by toxic molybdenum and fluorine are tolerated by plants but are toxic to animals that feed on them. constituents. To cope up with such problems, the information concerning the quality of irrigation Toxicity due to sodium and chloride are given in Tables 2 & 3 (Ayers and Branson, 1975) water and its effect on soils and crops is necessary. respectively. Usually the quality of groundwater for irrigation purpose is evaluated on the basis of total concentration of soluble salts or salinity hazards, exchangeable sodium or sodicity hazards, toxicity hazards due to specific constituents and other miscellaneous effects.

85 86 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Table 1- Toxicity guidelines for toxicity to boron (ii) Magnesium Hazard Paliwal (1972) has used the ratio (Mg2+ * 100)/(Ca2+ + Mg2+) as an index of magnesium hazard to irrigation water. Mg hazard is likely to be developed in the soil when this ratio exceeds 50%. The degree of hazardous effects would increase with the increase of Mg2+/ Ca2+ ratio. However the harmful effect of Mg2+ of irrigation water on soil is likely to be reduced 2+ by the release of Ca on dissolution of CaCO3 if present in the soil. (iii) Alkalinity Hazard This indicates the ability of the water to increase the pH of the soil or growing media, and the buffering power (resistance to change) of the water itself. In other words, the ability of the water to act as a liming agent. Alkalinity is defined as the combined effect of bicarbonates - -- (HCO3 ) plus the carbonates (CO3 ). High alkalinity indicates that the water will tend to increase the pH of the soil or growing media, possibly to a point that is detrimental to plant growth. Low alkalinity could also be a problem in some situations. This is because many fertilizers are acid-forming and could, over time, make the soil too acidic in nature for some plants. If the water is also somewhat acidic, the process would be accelerated. Another aspect of alkalinity is its potential effect on sodium (Na+). Soil or artificial growing media irrigated with alkaline water may, upon drying, cause an excess of available sodium. Several potential problems could result: n The excess available sodium could become directly toxic to some plants. n The salinity of the soil could be increased to the point that plant growth is damaged. n Excess sodium could damage the structure of natural soil to the point that air and water infiltration are prevented, and root growth is restricted. Danger from high alkalinity is governed in part by the volume of soil or artificial media involved. For example, greenhouse transplant production (plugs) have very little soil media Miscellaneous Effects and are less tolerant of a given alkalinity level than most other container production systems. In this category, problems related with crop production due to water quality, such as Field production will typically be the most tolerant. The alkalinity effects in irrigation water are excessive vegetative growth, white deposits on fruits or leaves due to sprinkling with high given in Table 4 (www.spectrumanalytic.com). bicarbonate water, and problems related to pH, Cl, Mg, alkalinity have been discussed. Table 4- Alkalinity hazard levels (i) pH The pH is a measurement of the relative acidity or basicity of the water. The pH range is from 0 to 14. Values from 0 to 6.9 are acidic and those from 7.1 to 14 are basic or alkaline, with 7.0 being neutral. The pH scale is logarithmic, meaning that a change of 1.0 unit is a ten- fold change in either acidity or basicity. Therefore, changes of less than 1.0 unit may be significant. This characteristic of the water has a significant influence on other characteristics or reactions in the soil and water, as well as the way plants perform. A water pH between 6.5 and 8.5 is normally considered to be the most desirable for irrigation. When the pH is outside of this range, it indicates that special actions may need to be taken to improve crop performance. 87 88 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

(iv) Bicarbonates (HCO3-) Hazard Among the components of water alkalinity, bicarbonates are normally the most significant concern. Typically, bicarbonates become an increasing concern as the water increases from a pH of 7.4 to 9.3. However, bicarbonates can be found in water of lower pH. Carbonates become a significant factor as the water pH increases beyond 8.0 and are a dominant factor when the pH exceeds about 10.3. High levels of bicarbonates can be directly toxic to some plant species. Bicarbonate levels above 3.3 me/l (200 ppm) will cause lime (calcium and magnesium carbonate) to be deposited on foliage when irrigated with overhead sprinklers. This may be undesirable for ornamental plants. Similar levels of bicarbonates may also cause lime deposits to form on roots, which can be especially damaging to many tree species. The bicarbonate effects in irrigation water are given in Table 5 and 6 (www.spectrumanalytic.com). Table 5- Bicarbonates hazard levels Fig. 1. Assessment of irrigation water quality for soils of different initial permeability (ii) On the Basis of Residual Sodium Carbonate A major factor affecting the final SAR value of soil water is the change in calcium and magnesium concentration due to precipitation or dissolution of alkaline earth carbonates. In irrigation water containing high concentration of bicarbonate ions, there is a tendency for calcium and, to a lesser extent, magnesium to precipitate in the form of carbonate as the soil solution becomes more concentrated, thus leading to an increase in the SAR of the soil solution. Although carbonate precipitation is common for many surface waters, its extent is *Bicarbonate levels above 3.3 me/l (200 ppm) will cause lime (calcium and magnesium often greater when well water is used. Eaton (1950) assumed that all calcium and magnesium carbonate) to be deposited on foliage when irrigated with overhead sprinklers. This would precipitate as carbonates and proposed the concept of residual sodium carbonate may be undesirable for ornamental plants. (RSC), for evaluating high carbonate water: -- - 2+ 2+ Table 6- Effects of high bicarbonate in irrigation water RSC(meq/l) = ( CO3 + HCO3 ) ( Ca + Mg ) High RSC water is considered to be deleterious to the physical properties of the soils. If irrigation water contained carbonate and bicarbonate ions in excess of magnesium and calcium ions, then there is a tendency for calcium and magnesium ions to precipitate as carbonates. As a consequence, the relative proportion of sodium ion increases and gets fixed in the soil by the process of base exchange and thereby decreasing the soil permeability. Threshold Classification of Irrigation Water values of RSC for irrigation water (USDA, 1954) are given in Table 7. (i) On The Basis of Permeability Index Table 7- Irrigation water quality on the basis of RSC Doneen (1964) has developed a chart (Fig. 1) based on the Permeability Index (PI) given by:

+ - 0.5 2+ 2+ + PI = {[Na + (HCO3 ) ] / [(Ca + Mg + Na )]} *100 where, all concentrations are in me/l. According to this classification, water is good if: - Its position in the US salinity diagram is within the zone of good or moderate waters. (iii) On the Basis of Soluble Sodium Percent (SSP) or Na% (Wilcox Classification) - It belongs to class-I or II in the Doneen (1964) chart (Raghunath, 1987). Wilcox (1948) has proposed another classification scheme for rating irrigation water on the basis of specific electrical conductance, soluble sodium percent (SSP) (Fig. 2). The SSP is calculated by the following formula:

89 90 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

SSP or Na% = [(Na+ + K+) * 100] / [(Ca2+ + Mg2+ + Na+ + K+)] Conclusion where, all concentrations are expressed in epm. To ascertain the groundwater resource in the shallow aquifers that gets annually recharged The following scheme (Table 8) of classification was given by Wilcox: through rainfall under varied hydrological conditions in the north east region, suitable scientific Table 8- Wilcox classification on the basis of Na% and conductivity techniques following well defined norms, need to be adopted. The north east region of India is endowed with groundwater resources, whose utilization in a planned manner on scientific principles will enhance its prospects for the years to come. Therefore, information related to suitability of groundwater for irrigation purpose on quality aspect is necessary. References Ayers, R. S., and Branson, R. L. (1975). Guidelines for Interpretation of Water Quality for (iv) On the Basis of US Salinity Laboratory Classification Agriculture, University of California, Extension Mimeographed, pp 13. High concentrations of exchangeable sodium in irrigation waters and soils cause the eventual deterioration of soil structure and resulting reduction in hydraulic conductivity. When Ayers, R. S. and West Cot, D. W. (1985). FAO Irrigation Drainage Paper 29 (Rev1), Rome, calcium and magnesium are the predominant cations occupying soil exchange sites, soils Italy. tend to have a granular structure that is readily permeable to both air and water. As the Doneen, L. D. (1964). Notes on Water Quality in Agriculture, Water Science and Engineering concentration of exchangeable sodium in the soil increases, the ratio of sodium to calcium Paper 4001, Dept. of Water, Science and Engineering, Univ. of California, Davis, USA. and magnesium ions rises and the number of exchange sites occupied by calcium or magnesium decreases. This causes soil mineral particles to disperse and hydraulic conductivity Eaton, F. M. (1950). Significance of Carbonate in Irrigation Water, Soil Sci, Vol 69 no. 2 pp to decrease. 123-133. The sodium adsorption ratio (SAR) of soil extracts or irrigation waters is used to evaluate James, G. Lary (1988). Principals of Farm Irrigation Systems Design, John Wiley & Sons, the exchangeable sodium status or sodicity hazards of soils and irrigation waters. The SAR New York. is generally a good indicator related to exchangeable sodium status of soil. The SAR is Paliwal, K. V. (1992). Irrigation with Saline Water, IARI, Monograph no. 2 (new series), New defined by the equation as given below: Delhi. SAR = [Na+] / [(Ca2+ + Mg2+)/2]0.5 Raghunath, H. M. (1987). Ground Water, Wiley Eastern Limited, New Delhi, India, pp. 456. all concentrations are in me/l in equation of SAR. Rhoades J. D. (1982). Reclamation and Management of Salt affected Soils after Drainage. The U.S. Salinity Proc. 1st Annual Western Provincial Cong. on Water and Soil Resources Management. Laboratory (USSL) has Lethbridge, Alberta Canada. pp. 123-197. constructed a diagram for classification of irrigation Shainberg, I. and Oster, J. D. (1978). Quality of Irrigation Water, IIIC Publication No. 2, waters describing 16 classes International Irrigation Information Centre, Volcani Centre, P.O.B. 49, Bet Dagan, Israel. (Fig. 3), with reference to U. S. Salinity Laboratory Staff (1954). Diagnosis and Improvement of Saline and Alkaline SAR as an index for sodium Soils, USDA Handbook no. 60, pp 160. hazard and EC (micro-mho/ cm) as an index of salinity Wilcox, L. V. (1948). The Quality of Water for Irrigation Use, USDA Tech. Bull. 162, Washington hazard (USDA, 1954). Thus, D.C., pp 40. U.S. Salinity diagram is a www.spectrumanalytic.com, Guide to interpreting irrigation water analysis, Spectrum Analytic, combination of salinity and Inc., USA. sodium hazards plotted on X and Y-axis, respectively. n n n Fig. 2. Wilcox Fig. 3. U.S. Salinity Laboratory classification classification 91 92 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

All the 20 nos Major/ Medium irrigation schemes( completed 16 nos. and ongoing 4 nos.) envisage provision of tens of canal falls to negotiate the steep gradients in canal geometry .To particularly make use of the live canal falls and also any small static water heads elsewhere Hydro Electric Power Generation in for generation of electricity, development of a suitable turbine is toyed. An attempt is made to discuss in the paper the various stages, parameters or other issues around the development Irrigation Canals of the turbine. The present self generating capacity of electricity in Assam is only 250 megawatts, whereas the peak demand for electricity in the state is 1100 to 1200 megawatts, which is only 20% of Kamal Ch. Saikia the peak demand. This is actually a matter of public concern since the price of per unit Junior Engineer, electricity would definitely be increased as it would be obtained from other sources. Therefore, Irrigation Department, Assam. a new innovation for generation of electricity in Assam is a must. The new propeller hydro turbine that has been toyed works on a new concept called "Displacement Phenomenon". There are enormous potential for generation of hydropower in irrigation canal falls and This Displacement Phenomenon states that the balance of the displaced water obtained canal drops in major and medium irrigation projects implemented by the Irrigation Department by subtracting the self mass (weight) of the propeller body from the total mass (weight) of of Assam. Basically, irrigation barrages and canal head regulators of medium flow irrigation displaced water displaced by the body of the propeller inside a turbocharged tank can be schemes are considered to be potential area where there may be 1.00m to 3.00m maximum fairly utilized as an ideal and effective propellant. static water head available throughout the year. Embankments of the canal head regulators Propulsion theory of the micro light propeller hydro turbine near the barrage, canal falls and canal drops facilitating flow of irrigation water to the canals and field channels of the paddy fields are regarded as the best sites for installation of micro- The balance mass of the displaced water inside the turbo charged tank is always remained hydel electric power generating turbine plants. These micro-hydel electric power generating constant, and will not be diminished during operational period as because the propeller turbine plants installed by the side of such irrigation structures serve the purpose in two body( being extremely light) is kept in complete immersion under turbulent water of the turbo charged tank, mounted vertically on the bearings fitted to the vertical propeller shaft. The ways. Firstly, these plants produce electricity which can be transmitted to the pump houses of v 2 3103.945313 Power expended irrigation department through step up transformers for running electric motor pumps at lift =mass of the balance displaced water will gain its full strength of kinetic energy ( mv 2 ) , and irrigation schemes and DTWS. The exhaust water coming out from the tailrace of turbine 4414.50 willPower start supplied moving along with the flow of water fed in to the turbo charged tank from a static house may be allowed to flow through the downstream of canals and finally to irrigate the head of water only 1.00 meter height. Due to the kinetic energy, the balance displaced water paddy field through field channels. Thus these micro-hydel sets will not only contribute towards exerts thrust force on the body of the propeller from the bottom to top and the upward moving generation of the electricity needed for running irrigation pump sets but also to supplement water strikes the blades and the moving water in the form of relative fluid flow exerts lift force towards domestic needs of beneficiaries from an irrigation schemes on the propeller body. In the context of ongoing power scenario of our state of Assam, it is necessary to find out (The formal design power is chosen as 6 H.P.) a possible means to overcome the power shortage that cripples the daily life of the people The formal design power is 6 H.P. or 6 x 75 = 450 kg. m./second. from all walks of life. To address the emerging issues, Govt of Assam has adopted policy for The formal power of the propeller is in Newton m/second. Is generation of electricity from low water head at various rivers, rivulets, streams and streamlets 450 x 9.81 = 4414.50 Newton m/second. across the state. Accordingly, Govt. of Assam has identified prospects for some 90 nos. of The outflow of the propeller is m V = 3103.945313 Newton m/second. small hydel projects in the state that have been cited in the Policy for Small Hydro power out

Development(March/2007). The inflow of the propeller is m Vin = 2337.088235 Newton m/second. Now the Discharge of water supplied to the propeller = 4414.5 Newton m/second. However, static water heads for these identified projects proposals range between 2.00m to 200.00m mostly range of 20.00m to 40.00m for generation of power ranging from 0.10 MW And the Discharge of water expended by the propeller to produce power = to 20 MW. 3103.945313 Newton m/second. Irrigation Deptt. of Assam has created irrigation potential of 8.23 Lakhs Ha. out of Ultimate Irrigation Potential of 27.00 Lakh Ha. by flow irrigation, lift irrigation, deep tube wells and Therefore, Efficiency = µ = shallow tube well schemes. Or µ = 0.70 = 70% 93 94 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Again, with the same transmitted torque Tp, 397.305. N, under the same static head of water (1.00m), the angular velocity is increased from 11.105 Radian/sec. to 22.85 Red/second and also RPM (N) of the main shaft is increased from 106 to 218 by the application of the principle of displacement phenomenon. Therefore, the increased power is 9078.42 N-m/sec. Analytical method using trigonometry :

The thrust force Fp = 766.8571 kgf Exerted by the propeller is the result of the lift force generated by the moving propeller blades, as w ell as the action of the up thrust on the propeller barrel exerted by the displaced water. The relative flow velocity Vb relative to the motion of the blades is the vector sum of the axial speed Vp of the fluid past the propeller minus the tangential speed of rotation of the propeller blades (ΩR). The blades are provided with an angle of attack of the blade cross- section with respect to the relative flow, as depicted in the fig. below (vector diagram). An incremental lift force dL acting on an increment of propeller span ds is generated by the ⊥ propeller blade foil. This lift force acts in a direction perpendicular ( ) to Vb, making an angle α with respect to the axis of rotation of the propeller. This lift force increment dL resolves itself into two components - one in axial direction (cosα) dL and the other in the tangential direction (sinα) dL, that respectively contribute increments dF and dT to thrust force Fp and torque Tp.

95 96 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Incremental lift force i) dF = (cos ) dL ------Eq. no. 1 ii) dT = R (sin ) dL ------Eq. no. 2 Where dT = (tangential force (sin ) dL x Radius) Eliminating dL, and nothing that -

From the equation no. (3), the incremental torque dT and incremental thrust force dF can be integrated along the total span of the propeller to give the magnitude of the torque T in the relation to the thrust force F.

Propulsion Efficiency :

Therefore, Propulsive efficiency =

Therefore, increase in propulsive efficiency is (79% -70%) = 9% as compared to 6.00 H.P. conventional propeller engine

97 98 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

99 100 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 Some Aspects heof tInstitutional Strengthening Component : AIFRERMIP

Dr. Ranjit Galappatti DHI Team Leader, ISC, AIFRERMIP

ABSTRACT The Assam Integrated Flood and Riverbank Erosion Risk Management Investment Program is a major new investment programme to increase the capacity for Flood and River Erosion Management in Assam to a new and sustainable level with strategies based on new knowledge bases and tools that will replace the previous reactive response to disasters with a proactive approach which uses all the tools at our disposal in consultation with riverine communities. The Institutional Strengthening Component (ISC) has to contribute towards creating knowledge bases and capacity building, particularly within the Water Resources Department, which is the principal executing agency responsible for this work. The ISC work has just begun. This paper anticipates some of the work to be carried out by ISC 1. Background Institutional Strengthening Component of the Assam Integrated Flood and Riverbank Erosion Risk Management Investment Program (AIFRERMIP) is a major investment programme of the State Government of Assam which is being implemented through the Flood and River Erosion Management Agency of Assam (FREMAA); an agency specially created for this purpose. The core project goals are n integrated flood and riverbank erosion risk management (FRERM) with community focus n institution building and change management including critical data and knowledge base The programme has many facets and some of them are serviced by separate consultancy packages. One of them is the Institutional Strengthening Component (ISC) being serviced by DHI (India), Water and Environment Pvt Ltd in association with WAPCOS Ltd. The consultancy with carry out the following: n Close knowledge gaps about the Brahmaputra River and its floodplain n Support development and establish an enabling environment n Support development and establish organizations and build capacity for integrated FRERM, n Advise on the implementation of structural measures, while ensuring quality works are implemented in a timely and adaptive manner,

101 102 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 n Advise on the development of non-structural measures with special focus on community based activities, n Advise on the development of an asset inventory system providing the basis for programming adaptation and maintenance work. n Carry out formal and non-formal training activities related mainly to development of FRERM planning, institutional and knowledge bases. These objectives are broad and will require analysis of organisational needs and knowledge deficits in the fields of flood and erosion control and management, existing mechanisms for Brahmaputra Survey Vessel Bottom Mounted ADCP Typical ADCP Velocity Plot responding adequately to community needs etc., before the final work plan is prepared. The behaviour of the river in Assam is very similar to how it behaves in the lower reaches, This paper will outline our approach towards implementing some of the major strands of except in two very important ways. Firstly, the upper reach in Assam has huge volumes of our assignment and to provide examples of previous (or concurrent) activities of DHI which inflow from tributaries which increase the annual volume by 40 per cent within a relatively are relevant to this work. short reach of this long river. The Jamuna in the lower reach has only two significant tributaries, 2. Understanding the Brahmaputra River the Teesta and the Atrai, within Bangladesh. Secondly there are three natural and permanent Managing this most difficult and complicated river requires a very sound understanding of constrictions of the river (e.g., rock outcrops) within Assam that force the river to reduce to a the physical processes that drive the water and sediment in this river and how the river single channel and expand to its natural braided pattern downstream once again. There are responds to the hydrological events that brings in water and sediments along all its tributaries. no such natural constrictions in Bangladesh, but the Jamuna Bridge river training works The Brahmaputra River has given rise to a great deal of literature describing its entire constitutes a recent man-made and permanent constriction. course from Tibet to the Bay of Bengal. Much of this describes the geography and culture 3. Modelling Morphological Change along the river from the observations of generations of explorer, adventurers, geographers, Much could be learned about the past behaviour of the river by studying planform changes historians and scholars. Until modern times there have not been any detailed scientific studies using satellite imagery. Much detailed analysis using the development of sedimentary features of the nature of hydraulic and sedimentological processes within the river that made it possible to understand, quantify and eventually predict the apparently unruly behaviour of this river. etc., has been made to extend the This is most applicable to the braided reaches downstream of Pasirghat - that flows first methodology developed in Bangladesh through the plains of Assam and then into Bangladesh as the Jamuna until it joins with the for predicting planform changes in the Ganges at Aricha. Jamuna River to some reaches of the Brahmaputra in Assam1. The final report The valley slope, the flow regime and the sediment load carried by the river (now running in of this study has not been published yet. its own alluvium) have conspired to make this a highly braided river with a continuously changing Such analyses will form the initial step braiding pattern of several intertwined channels have that have over the centuries proved to be in identifying critical areas for further impossible to control and difficult to predict. Detailed studies of the river in Bangladesh, particularly study and for proposing interventions the formation, propagation and decay of different sizes and types of bedforms and their where necessary. Any small disturbance relationship to the flow were carried out in the late 1960¡¦s by J.M. Coleman. Systematic discharge can cause braiding of a river channel if measurements and suspended sediment sampling programmes were set up during the same the flow and sediment regime are right. period. There were no other serious large scale measurement programmes on the lower The figure to the left shows how a very Brahmaputra (i.e. in Bangladesh) for the next three decades ¡V until the River Survey Project long MIKE21C simulation that begins (Flood Action Plan Project No. 24) of the mid 1990s, when a complete update of the measurement techniques was undertaken by a joint team from DHI and Delft Hydraulics. A very large number with a smooth rectangular channel with of modern measurement methods suitable for use on large sediment laden rivers were tried the average hydraulic characteristics of 3 out and their results compared. During this long project a very large amount of data was the Jamuna River (Q=45,000 m /s, D50 accumulated and this allowed detailed interpretation and enabled a deeper understanding of = 0.16mm, 10 km initial width and the hydraulic and sedimentological processes involved. Of the new measurement methods erodible banks etc.) can eventually introduced was the Acoustic Doppler Current Profiler (ADCP). become a braided channel, eerily similar

103 104 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 to the actual Jamuna braid pattern. Any infinitesimal disturbance (such as computer digit 4. Enabling Effective FRERM round-offs) was enough to trigger the development of this braided channel in the model. This Developing capacity for Integrated Flood and Riverbank Erosion Risk Management is not an unstable condition but actually the prevailing stable pattern with the given valley (FRERM) is the main objective of the investment programme. In order that this object is slope, flow and sediment load. achieved, all the different elements of the project must come together. When a site has been identified for protection works, and a set of interventions are proposed, Embankment building programmes for flood protection have been active for more than 50 it is useful to use mathematical models such as MIKE21C to provide more detailed design years. 4,856 km of flood embankments have been built in Assam so far; but not with uniform information such as success. The approach has always been reactive, and in response to a failure or an imminent a) The impact of the proposed structures on the near field morphology (viz. scour depths) threat. Planning of emergency works rarely take the views of the community into account ¡V and velocity field. although public demand is often the trigger for obtaining support for carrying out an intervention. b) Impacts on river banks and the river in the adjacent river reaches. The feeling has also grown that much of the investment has been wasted because flood and c) Identification of knock-on effects that require immediate remedies erosion risk are still ever-present. d) Far downstream effects This new project will make it possible to intervene proactively in the process of flood and The utility of MIKE21C software in providing this information have been demonstrated erosion risk management. The following new elements are being introduced: many times in many countries. These model simulations should not only be done for average a) Improved knowledge base will promote better understanding of the physical processes flow conditions but also for extreme conditions depending on the return period applicable to the design. The possibilities of the upstream approach flow having a different alignment b) Active stakeholder consultation as well as stakeholder education would be providing should also be taken into account in the scenarios to be modelled. valuable inputs to the planning process This approach could not be followed in the bank protection schemes presently under c) Advanced modelling and other predictive tools such as analysis of satellite imagery would construction. It is however worthwhile carrying out the modelling exercise at these sites to make risk assessment less prone to error and allow identification of critical areas more determine the completeness of previous proposals. accurately Measured Bathymetry Computed Bathymetry d) Modelling and other prediction tools could firm up design parameters for the structures e) Modelling and other prediction tools could quantify impacts of the proposed designs enable mitigation to be built in to the design In addition to the above the project will develop a Management Information System (MIS) which will be based on an extensive and all-encompassing database which will contain, inter alia a) A full inventory of all existing river infrastructure, their locations (within a GIS), their present condition and usefulness, whether any improvement or renovation is planned etc. b) An inventory of all proposed new infrastructure, their current planning/design status c) An inventory of all construction already in progress ¡V their construction status etc. ¡V including such information as cost over-runs, d) The database should be designed to include socioeconomic data related to the land and the community served by the infrastructure. The mere storing of this data would not serve any purpose unless there is a well-designed MIS tool which can access it and serve the needs of multiple groups of users within WRD and FREMA depending on their needs and permitted levels of access. The possibilities are very broad. The actual design would depend on the clients¡¦ requirements. Verification of Morphological Model of Impacts of Jamuna Bridge Training Works 105 106 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Remote access to the MIS would require the existence of a computer intranet within WRD Lanka Hydraulic Institute (LHI) was set up as a and FREMAA. There are many other ways in which the introduction of IT could modernise local centre of excellence ¡V by converting the and improve the effectiveness of WRD. These possibilities have also to be explored. Coastal Engineering Research Centre of the 5. Capacity Building and Sustainability Government of Sri Lanka into a government owned public company. The CERC had already received The ISC component is expected to leave behind a permanent indigenous capacity for substantial aid from DANIDA via DHI for equipment FRERM creating an enabled environment among institutions that can function effectively and for training of engineers and technicians. and efficiently in carrying out their work. There are many strands to this work. They are Despite the presence of well-trained local staff 1) Capacity building through training and the introduction of new technologies and supervised by DHI advisors, the operating rules techniques, and better management infrastructure for improving the productivity of within the government set up could not bring technical personnel at WRD. productivity up to the levels expected in such a modern facility. After changing the nature of the 2) Widening the horizons of planners and decision makers with familiarisation visits to institution in 1985 it has become and remained other countries viable and stayed independent of any external 3) Training of selected young professionals in advanced modelling and GIS techniques ¡V assistance for 25 years. It now does work all over first in India and then in Denmark Asia including India. The other, much larger, example is the Institute of Water Modelling (IWM) 4) Finding ways to build an institution that could fully assimilate the new knowledge into its in Bangladesh which began as the Surface Water fabric so that what has been gained will be sustained for the future beyond the termination Modelling Programme, again a DANIDA project of this project implemented by DHI. DANIDA thoughtfully agreed to extend the project into a final institutionalisation There have been many ¡§Technology Transfer¡¨ aid projects in many countries in the last phase during which it was possible to set up the 50 years. Very few of these have been successful. Most recipients of such aid have had to Surface Water Modelling Centre ¡V now IWM. This return to the same donor or other donors within 5 years requesting another injection of is a totally independent water consultancy organisation specialising in modelling and field ‘‘Technology Transfer’’ to rehabilitate or renovate the remnants of the previous project which measurements. Again this organisation can function and prosper without any financial support had been allowed to decay. The human resources developed earlier had dispersed either from the government or any donor. They are the foremost exponent of the advanced MIKE21C through the attractions of the first world or due to the frustration of using new methods in an morphological modelling in the region environment locked into old ways of thinking. It is important to understand why some efforts at sustainable capacity building succeed There have been notable successes too. There are two South Asian examples that are while many others fail. Three important aspects are: very relevant. Both examples are of projects that happened to be implemented by DHI-V a) The consultant did not simply do the work; deliver a good finished product and leave. which was then known as Danish Hydraulic Institute. The recipients actually did most of the work under the guidance of the consultant and after receiving sufficient training. b) The on-the-job interaction between the training provider and the trainees continued over several years in an environment conducive to high productivity. c) The focus from the beginning was on institution building ¡V and not just on human resource development. It was necessary that the trained personnel would be motivated to stay and work in an institution with a good working culture and which offered reasonably competitive salaries. d) The new institution should also have a viable business model. CEGIS the other well-known institute in Bangladesh was set up along the same lines as SWMC after seeing the success of the latter, seeing that this the best way of sustaining the GIS technology including satellite imagery analyses acquired during the Flood Action Plan .

107 108 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

6. Real Time Flood Forecasting The activities Model Deflector as Safety Measure to described and explained briefly above form a representative sample, Embankments temsy of Flashy River but there are also other aspects that have not Er. Utpal Majumdar been mentioned. The Asstt. Executive Engineer foremost among them is Water Resources Department the subject of Flood Forecasting and ABSTRACT Warning. The Disaster It is a demand of time to think of an alternative anti-erosion work instead of traditional type, Management Authority which will be full proof and permanent in nature in the basin of a flashy river. has the benefit of an effective flood warning The main aim is to protect the marginal embankments from erosion by deflecting the flow system based on from embankment system. This model is an RCC barrier extending from embankment to river detailed analyses of side. It is composed of RCC piles connected with RCC wall of required thickness as per design water levels in the river based on scour depth consideration and lateral load due to water. system. However, it is Provision of RCC deflector along with necessary measures for arresting soil mass in the possible to introduce a upper catchment may prove to be a sustainable anti erosion and flood management plan of a much more accurate flashy river. real-time warning system Rising of river bed due to marginal embankment is not a new thing now. This problem has based on proven been faced globally by all. Normally the river/ rivulets in the upper catchment has steep technology for which the necessary training and capacity building would also be carried out gradient. When it passes through the plains, its velocity decreases compared to the upper by ISC. The institutional analysis is still incomplete. The Inception Report of ISC would outline reach. Flood water during rainy season carries huge quantities of soil load in the form of Silt, these activities. Sand, Stone and Boulder etc. Silt deposition starts in the plains when velocity of water DHI has experience of setting up successful real-time flood forecasting and warning decreases. When the rivers are confined by marginal embankments, the country side/ land systems in many parts of the world ¡V including Bangladesh and elsewhere in India. The side remains cut off from the river. Thus, silt deposition is only occurs in the area between the setting up of such a system in Assam would require careful handling of the very flashy northern marginal embankments i.e. in river bed. This process of silt deposition continues year after tributaries of the Brahmaputra and strengthening the existing data network. year decreasing water way or water carrying capacity of a river/ rivulet. Frequent raising and The schematic layout of the Krishna Bhima Real time Flood forecasting system that makes strengthening of embankment systems has been a needed job. The silt content of rivers use of real time data acquisition as well as historical databases is shown below. increases also year after year due to deforestation and other development work in the upper 7. Conclusion: This paper gives a brief and partial overview what the ISC component hopes catchment like construction of roads, buildings etc. So, a permanent like sustainable solution to achieve. The work of ISC is complementary to that of the Project Management Consultant will be treatment of upper catchment from where the rivers/rivulets come out. If the upper (PMC) which has a different focus. There are, however, many areas of overlap between the catchment is protected with vegetations cover and other structural measures, the silt load to two consultancies. There is already a well-established and strong continuing dialog between the rivers will definitely come down. PMC and ISC to ensure that the work programmes will go forward together to the benefit of Jiadhal is one of the examples of flashy river in Dhemaji. The area between the marginal the overall Assam Integrated Flood and Riverbank Erosion Risk Management Investment embankments has been rising year after year due to silt deposition. Present water way is Program (AIFRERMIP). The Inception Report of ISC would outline these activities. about 10 to 20 percent of the original waterway that was 30 to 35 years ago. In this write up The success of ISC would depend, to a great extent on the cooperation and goodwill of it is attempted to discuss the problems and probable solution with special reference to Jiadhal our counterpart organisations. This cooperation is essential for our objectives of institution river in Dhemaji. building and change management. I am pleased to be able to report that the ISC team has Problem: met with an open and welcoming attitude among everyone we have interacted with so far. It bodes well for the future of our assignment towards enhancing Assam Integrated Flood and From the experience in the field with flashy rivers, it is observed that most of the breaches Riverbank Erosion Risk Management. n in embankment occur due to erosion. Occurrence of breach due to overtopping is less. Once

109 110 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 erosion starts in a location it becomes very much difficult to keep it under control, because of As the flashy rivers have a tendency to braiding, this model deflector may be provided at the properties of soil which is sandy. Due to deposition of soil in one bank it restricts the water the locations where the river approaches to an embankment threatening severe erosion. way to become very narrow to other bank and as a result water flows in very high velocity. Year after year, if these deflectors are provided, as and when required, there will be a time High velocity of water washes away sandy soil at the toe of embankment first. Then when the flow of river will be restricted in between rows of deflectors only. Bank erosion will unsupported soil mass above toe slips down easily due to its own weight and due to absence come down to a great extent. Frequent raising and strengthening of the embankment may of clay content which has the property of arresting soil particles. Again a number of channels also be reduced, if the upper catchment is treated scientifically arresting the soil mass. those are present between the marginal embankments change course frequently which is For better appreciation a model drawing of deflector along with design calculation and a braiding in nature. Traditional anti-erosion works could not stand effectively. model estimate has been framed as follows. Anti-Erosion Measures so far Taken up: Length of Pile Considering Scour Depth: In last several years, different anti-erosion works had been taken up. They are- Boulder Assumptions: Spur, Boulder apron, Boulder revetment, Bamboo spur, Bamboo screen, Geo-bag apron, Geo- bag revetment, RCC porcupine screen etc. Submersible vanes have also been Velocity, v = 5.00 m/sec experimented recently to control erosion. During flood season, bamboo bundles, Tree branches Max. Depth of Water, h = 2.00 M etc. are launched to control erosion in a particular area. Discharge per metre = 10.00 Cumec Effectiveness of Anti-Erosion measures: water way, q Almost all of them could not stand or has not been effective up to expectation. Perhaps, Mean weighted dia., md = 0.265 mm the main cause of it is less attention given to site exploration. The area where anti-erosion works had been taken up is sandy soil i.e. foundation or base of Anti-erosion work is purely Lacey's Silt factor, f = 1.76x√md sand. There is a layer of clay at about 10 ft (3.00 m) depth from existing river bed. The whole = 0.91 soil mass above clay layer remains saturated and has mobility in some extent. This sandy Normal scour depth, by soil mass cannot withstand high load like boulder. It starts sinking after construction. Similarly, Lacey's Formula, the RCC porcupines also settle down in the soil mass. As they sink in the sandy soil mass, 2 (1/3) they no longer serve the purpose. In the case of bamboo screen and other bamboo anti RL = 1.35 (q /f) = 6.47 m works also, the bamboos lose grips with sand due to vibration and there remains a tendency Depth of Pile from HFL = 1.5 R to lift up due to thrust of deposited floating garbage and buoyancy. L = 9.71 m Site Exploration: Depth of Pile from Bed Level = (1.5R-Depth of Water) Site exploration is highly necessary for formulation of a project. If the depth, extent, thickness L of sub-soil and their engineering properties are known: we can design a safe structure. Site = 7.71 m exploration is done for all engineering structures like road, building, bridge etc. Site exploration Say = 8.00 m should be an integral part for flood control structures also. Mere designing an anti-erosion work based on velocity, specific gravity of material, silt factor etc. is not sufficient. Calculation of Bending Moment on Pile for Model R.C.C. Deflector: Solution: Assumptions: Diameter of pile = 45 cm In view of the above, it is a demand of time to think of an alternative anti-erosion work Length of Pile = 8.00 m instead of traditional type, which will be fool proof and permanent in nature in the basin of a flashy river. A model of the same has been stated below. Spacing in a row = 2.50 m This model may be suitable only for flashy river having sandy soil deposition and vulnerable Max depth of water = 2.00 m to erosion. The main aim is to protect the marginal embankment from erosion by deflecting Velocity of flow = 5.00 m/sec the flow from embankment system. This model is an RCC barrier extending from embankment g = 9.81 m/sec2 to river side. It is composed of RCC piles connected with RCC wall of required thickness as w = 1000.00 Kg/m3 per design based on scour depth consideration and lateral load due to water. RCC barrier in the form of sheet pile may be extended to impervious clay layer or to the extent required as E = 3000000.00 N/cm2 per design through the sandy bed as a cut-off. ? h = 20.00 N/cm2

111 112 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

I = 201369.98 cm4 Location of Maximum = 175 cm Load on Pile: Bending Moment, Z.T Head of water = 2.00 m Below ground surface = 1.75 m Lateral load- Mmax = 13242310.63 N-cm Velocity head, v2 /2g = 1.27 m Mmax = 132.4231 KN-m Total head, h = 3.27 m Refernece Book: Water Pressure for single span, Soil Mechanics and Foundations by Dr. B.C. Punmia 2.50xwh2/2 = 13366.125 Kg Circular Pile Design Detail Report :

Lateral Load, Pt = 133661.25 N (Design by limit state method as per IS 456 : 2000) Terms Used In Calculation : Moment, Mt = 5000.00 Nm Deflection of Pile: T = (EI/ ? h)1/5 In biaxial column design, P = P + P = 125.00 cm u uc us(Total) where, Maximum deflection of pile, Ymax Pu = external axial compressive load, 3 2 Ay.PtxT /EI+ByxMtxT /EI =1.05 cm Puc = axial compressive resistance offered by concrete, Maximum Bending Moment: Pus(Total) = total axial compressive resistance offered by steel

Mmax=AmPtT+BmMt at different levels in the section. M = M + M Where, PtT = 16707656.25 u uc us(Total) where, Mt = 500000.00 M = external moment about centroidal axis, Table for calculation of M u MAX M = moment of resistance offered by concrete in compression, Z=x/T A B Bending Moment uc m m M = total moment of resistance offered by steel at different levels in the section. 0.5 0.459 0.976 8156814.22 us(Total) i = serial no. of row of reinforcement, 0.6 0.532 0.960 9368473.13 A = cross-sectional area of reinforcement in the i th row, 0.7 0.595 0.939 10410555.47 si f = stress in the reinforcement in the i th row (compression + ve, tension - ve), 0.8 0.649 0.914 11300268.91 si f = compressive stress in concrete at the level of i th row of reinforcement, 0.9 0.693 0.885 12020905.78 ci e = strain at the i th row of reinforcement from the stress-strain curve of steel 1.0 0.727 0.852 12572466.09 i and concrete, 1.2 0.767 0.775 13202272.34 x = distance of the bars in the i th row from the centroid of the section 1.4 0.772 0.688 13242310.63 i 1.6 0.746 0.594 12760911.56 Values of stress in steel : 1.8 0.696 0.498 11877528.75 Design strength in bending compression (f ) = 0.87 fy 2.0 0.628 0.404 10694408.13 yd Maximum Bending Moment = 1.4 (a) Fe 250, Occurs when, Z For ei >= fyd / Es, fsi = fyd 113 114 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Column Name Orientation Angle For ei < fyd / Es' fsi = ei x fyd (b) Fe 415, C1 0.00 Check For Slenderness : For ei >= 0.8 x fyd / Es' fsi = value obtained from stress-strain curve Slenderness Ratio X = (L x Effective Length Factor X) / Depth For ei < 0.8 x fyd / Es/ fsi = ei x fyd 0 Stress Stress level Strain = (3750x1.000)/450 = 8.33 <=12.00, (N/mm²) column is not slender in this direction.

0.800 fyd 288.7 0.00144 Slenderness Ratio Y = (L0xEffective Length Factor Y ) / Width 0.850 f 306.7 0.00163 yd = (3750x1.000)/450 = 8.33 <= 12.00, 0.900 f 324.8 0.00192 yd column is not slender in this direction.

0.950 fyd 342.8 0.00241 Mx_MinEccen = 0.169 kN.m

0.975 fyd 351.8 0.00276 My_MinEccen = 0.169 kN.m

1.000 fyd 360.9 0.00380 Mx = max(Mx,Mx_MinEccen) + MuaddX = 198.630 kN.m Values of stress in concrete : My = max(My,My_MinEccen) + MuaddY = 0.169 kN.m

For ei >= 0.002, fci = 0.446 fck Design Moment,(Mudes)= sqrt(Mx² + My²) = 198.630 kN.m For ei < 0.002, fci = (446.ei x (1 - 250.ei)) x fck Values of strain : Calculation Of Eccentricities : Values of strain at different levels are obtained by taking maximum strain As per IS 456: 2000 Clause 25.4,all columns shall be designed for minimum eccentricity as 0.0035 as the reference value at the highly compressed edge. equal to the unsupported length of the column/500 plus lateral dimension/30, subject to a minimum of 20 mm. Design: Actual eccen = M General Design Parameters : X x/P = 198.63/7.50 = 26484 mm Actual eccenY = My/P = 0.00/7.50 = 0 mm Level at 3.750 m from top eccenXMin = (L/500) + (D/30) = (3750/500) + (450/30) = 23 mm Column size, (D) = 450 mm eccenXMin = max(23,20)

Column height, (L) = 3750 mm eccenYMin = (L/500) + (B/30) = (3750/20) + (450/30) = 23 mm eccen = max(23,20) = 23 mm From analysis results, loads on column YMin eccen = max(Actual eccen ,eccen ) = max(26484,23) = 26484 mm Axial load,(P) = 7.50 kN X X Min eccenY = max(Actual eccenY,eccenMin) = max(0,23) = 23 mm Moment X,(M ) = 198.63 kN-m x eccen = sqrt((26484 x 26484)+(23 x 23))

Moment Y,(My) = 0.00 kN-m = 26484 mm fck = 20.00 N/mm² As per IS 456: 2000 Clause 39.3, f = 415.00 N/mm² when the minimum eccentricity does not exceed 0.05 times the lateral dimension, the column y will be designed as an axially loaded column. Load combination = 1.50 DL + 1.50 LL 115 116 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 eccenX(26484 mm) > 0.05 x 450(23 mm) Calculation of diameter of ties : and eccenY(23 mm) > 0.05 x 450(23 mm) As per IS 456: 2000 Clause 26.5.3.2 (c), the diameter of the polygonal links or lateral ties Hence the column will be designed as a column with biaxial moments. shall be not less than the following Provided steel : i) one-fourth the diameter of the largest longitudinal bar = 16/4 = 4 mm Provide #16 - 12 nos. (2413 mm²) ii) in no case less than = 6 mm Biaxial Check Calculations : Required diameter = maximum of (4, 6) = 6 mm

Row No. Asi ei fsi fci (fsi - fci)Pusi xi Musi Provide 8 mm diameter for ties. (i) (mm²) (N/mm²) (N/mm²) (N/mm²) (kN) (mm) (kN-m) Calculation of spacing of ties : 1 201 0.00251 345.47 8.92 336.55 67.67 177 11.98 As per IS 456: 2000 Clause 26.5.3.2 (c), the pitch of transverse reinforcement shall be not 2 402 0.00237 341.21 8.92 332.29 133.62 170 22.69 more than the least of the following distances: 3 402 0.00194 325.42 8.91 316.51 127.27 149 18.95 i) the least lateral dimension of the compression member = 450 mm 4 402 0.00126 251.82 7.70 244.12 98.17 116 11.38 ii) sixteen times the smallest diameter of the longitudinal reinforcement bar to be tied 5 402 0.00039 77.70 3.13 74.57 29.99 74 2.20 6 402 -0.00060 -120.89 0.00 -120.89 -48.61 25 -1.22 = 16 x 16 = 256 mm 7 201 -0.00164 -307.28 0.00 -307.28 -61.78 -25 1.56 iii) 300 mm 8 402 -0.00263 -348.52 0.00 -348.52 -140.15 -74 10.30 Required spacing = minimum of (450, 256, 300) = 256 mm 9 402 -0.00350 -358.30 0.00 -358.30 -144.08 -116 16.70 # Provide ties 8 @ 250 mm c/c 10 402 -0.00418 -360.90 0.00 -360.90 -145.13 -149 21.61 11 402 -0.00461 -360.90 0.00 -360.90 -145.13 -170 24.65 12 402 -0.00476 -360.90 0.00 -360.90 -145.13 -177 25.69 SUMMARY : Total -373.28 166.49 Level at 3.750 m form top Provide circular section : 450 mm dia. xu = 170 mm Provide #16 - 12 nos. (2413 mm²) Puc = 370.04 kN Provide ties #8 @ 250 mm c/c Pu1 = Puc + Pus(Total) = 370.04 + (-373.28) = -3.25 kN

Muc = 52.22 kN-m

Mu1 = Muc + Mus(Total) = 52.22 + (166.49)

= 218.71 kN-m > Mudes,hence O.K. Ties Details : Load combination for ties design=1.50 DL+1.50 LL

117 118 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Basin level integrated water esourr ces management (IWRM) and eco-system management-A strategy ot respondo t climate change

S. C. Patra Professor, Water Resources Engineering NERIWALM, Tezpur

River Basin River basin is a 'geographical unit' enclosing an area drained by streams and channels that feed a river at a particular point. All the precipitation that falls on these area will either evaporate, used by plants and other living organisms, sink into the ground or end up in the river after various natural and man-made uses. Thus, it follows that river basin provides an important region to understand the implication of any particular form of human use of water and also relationship between precipitation, surface water and ground water. Integrated Water Resources Management (IWRM) If such steps are taken, perhaps we need not to worry with the future, as that will only be a little bit worse than what we have faced today. The concept of Integrated Water Resources Management (IWRM) emerged round the 1980s in response to increasing pressures on water resources from competition amongst n n n various users for a limited resource, the recognition of ecosystem requirements, pollution and the risk of declining water availability due to climate change. IWRM addresses the "three E s": economic efficiency, environmental sustainability and social equity, including poverty reduction. The three basic "pillars" of IWRM are the enabling environment of appropriate policies and laws, the institutional roles and framework, and the management instruments for these institutions to apply on a daily basis. IWRM addresses both the management of water as a resource, and the framework for provision of water services to all categories of users, and it addresses both water quantity and quality. In doing so, the basin (river, lake or groundwater) must be recognized as the basic unit for planning and management, and a firm societal commitment and proper public participation must be pursued. India has not yet reached the level of Water Resources Development as has already been achieved by many developed countries, therefore, there is a need for India to undertake developmental measures along with management measures. Assam having vast surface and ground water resources should embank upon IWRM for sustainable development and use of water for various purposes. 119 120 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

A central goal of IWRM at the river basin level is to achieve water security for all purposes, to speci?c economic, social or environmental activities and that depend in whole or in part as well as manage risks while responding to, and mitigating disasters. The path towards on water to ful?ll their needs and roles. Water resources development coordinated among water security requires trade-offs to maintain a proper balance between meeting various the various sectors and users is facilitated by the preparation of a master plan re?ecting sectors' needs, and establishing adaptable governance mechanisms to cope with evolving individual sector plans, and offering the most effective and efficient utilization of a basin's environmental, economical and social circumstances. resource. sectoral water allocation to the co-basin states should be periodically reviewed IWRM is de?ned by the Global Water Partnership (GWP-2000) as a process which and revisited. promotes the coordinated development and the management of water, land and related Good Knowledge of Natural Resources Present in the Basin resources, in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital IWRM for the provision of water Adequate knowledge and information on the water resources inventory and human services at the river basin level. This is advocated by the central Government. The resources of the basin is desirable. In many basins, however, it may be necessary to issue has been discussed in several forums. Some states have gone ahead in inititiating embark on developing a water resources management plan with available data and implementation of this concept. It is a holistic approach that seeks to integrate the management information. Maintaining and acquiring sound knowledge of the natural resources in the of the physical environment within that of the broader socio-economic and political framework. basin and ensure that it is strongly supported by scienti?c analysis. Further scienti?c studies, The river basin approach seeks to focus on implementing IWRM principles on the basis audits and investigations can be targeted at key areas for improvement in resource of better coordination amongst operating and water management entities within a river management decision making. Water Resource managers should therefore include scientific basin, with a focus on allocating and delivering reliable water-dependent services in an minds for water related studies. A well defined water related data collection network including equitable manner. its quantity and quality are key to planning, development and management of water resources. Embarking on IWRM in a river basin In this regard, Water Resource Information System (WRIS) at the national level and North Eastern Spatial Data Information (NESDI) for the region one important inititiatives for web The need of a country or a state for water resource management varies according to its based servicing of spatial data. characteristics - its geography, climate, size, population, political and cultural systems, level of development, and the nature of its water resource problems. Within a river basin, different Role of River Basin Organizations areas have diverse water problems and challenges. Each state and river basin must chart its River Basin Organisations provide an appropriate institutional mechanism to facilitate own vision and formulate plans based on its unique situation. Constructing infrastructure implementation. A major role of Basin Organisations is basin-wide planning to cater to all that can meet the demands of multiple sectors while ensuring water for irrigation and users' needs for water resources and to provide protection from water-related hazards. functioning of ecosystem as well as preventing negative impacts of ?oods can be given Their role involves wide public and stakeholder participation in decision-making, group as examples of an integrated approach. Basin activities, such as development or land involvement and empowerment at all levels. Attention should be paid to gender and use, that may impact water resources and the hydrological characteristics in the basin minority issues, effective demand and bulk water management, agreements on commitments must also be considered, while taking into account the social and cultural implications of within a basin relating to the quantity, quality, and efficiency of resource management and the population residing in the basin. Part of an IWRM approach is to characterize the present mechanisms for monitoring those agreements, and adequate human and ?nancial situation and use this and other information to anticipate future changes and develop climate resources. Basin organisations are successful when they are structured to provide change resilient strategies. partnership and consultation processes among the members, involving high-level Basin Management Plan and Clear Vision decision-makers and expertise in all aspects of integrated natural resource planning, IWRM at the river basin level is a continuous process working towards a basin development implementation and management. plan. A clear vision should specify the area as well as the level of safety to ensure project The application of IWRM by Basin Organisations varies according to each river basin's execution. The services, expected bene?ts and effects of each project should be clearly speci?c conditions and requirements. Many river basins have set up coordinating bodies to presented in line with various agreements and the appropriate balance of related sectors. facilitate river basin management. These may take the form of informal committees or Periodic reviews of progress are important to consider changes in national policies and authorities with important mandates and authorization. Decentralization and participation of other plans managed by sectors not directly related to water issues. the private sector has opened the way, in some countries, for the adoption of institutional Water Allocation Plans mechanisms based on the concept of integrated management of river basins, through Water is a shared resource among various sectors - including domestic water supply the transfer of responsibilities for the management of the resources from the ministries of & sanitation, irrigation, industrial sectors, and hydropower generation - that relate individually the central government to local governments, to autonomous public corporations or to the

121 122 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 private sector. Asian Developmental Bank (ADB) is setting an example by initiating good n There is need for optimum use of local sources of water even in canal-irrigated areas, in number of projects in Mekong river basin and lesson can be learned from them for application the interests of optimal water use, extension of irrigated land, prevention of water logging in the NE region. and increased productivity. Inter State Issues n Due importance should be given to local water planning, with the ultimate aim of making Potential con?icting interests in interstate river basins can be overcome through mutual each rural area manage its own water needs as far as possible through water harvests, trust and understanding between the States, appropriate legal and institutional frameworks, conservation measures and watershed development. joint approaches to planning and management, and sharing of the ecological and socio- n At every stage, from the very beginning, people concerned must be involved in working economic bene?ts, and related costs. Any River Basin Organisation (RBO) may face a wide out the project plan. A data base needs to be established and constantly updated at the array of challenges depending on its unique situation. Nevertheless, the overall water district level. management process at the basin level is easier. More options, including multi-purpose uses and joint projects, appear when issues and relations between riparian States and n State Governments should establish technical bodies at the local level for constant related sectors are treated together. Top-down basin-wide approaches based on interactive relationships between the programmes and the people on technical matters constructive ambiguity principles are often essential to foster trust and trigger action for and for use of low-cost and local materials. cooperation due to the political nature of allocation of interstate water resources. A fully National Water Policy integrated approach to manage water in a basin may not be immediately possible. However, The Draft National Water policy -2012 in para 9.2 states "Being inter-disciplinary in nature, this does not prevent embarking on IWRM at the basin level whether the process is well water resources projects should be planned considering social and environmental aspects developed or not. Various water-related sectors or users should be considered in a well also in addition to techno-economic considerations in consultation with project affected and coordinated manner, highlighting the interactions among them, their activities and beneficiary families. The integrated water resources management with emphasis on finding associated infrastructure. Seeking solutions to interstate issues can be attempted through reasonable and generally acceptable solutions for most of the stakeholders should be followed some of the available mechanism. for planning and management of water resources projects". Water Availability and Requirements River basins of North Eastern Region. n The work of refining the assessment of water resources of various basins using modern technology and collect reliable data pertaining to observed flows, utilization from surface The North eastern region is surrounded by Tibet, Bhutan, Myanmar, Bangladesh, West and ground water resources for irrigation and from other uses from surface as well as Bengal. There are many small, large rivers flow in the region and most of them are inter state ground water resources need to be undertaken. There is also a need to develop uniform rivers. Brief particulars of the river basins of the region is given in table-1. Individual basins of guidelines for assessing water resources potential and assessing water requirements substantially large area and group of basins having small area can be proposed for river for various uses. basin organizations in Assam n Impact on climate processes e.g. meteorological cycles, day/night temperature variations Table:1 Sub-Basin and State/Country wise catchments areas of River systems in NE etc consequently influencing rainfall and runoff, evapo-transpiration, crop water region having areas in Assam requirements etc. observed through General Circulation Models (GCM) / Global Climate Sl. River Basin/ Name of the Total Catchment Catchment Area Models will have to be suitably addressed through appropriate mechanism in each River No Sub-basin Basin Area (sqkm) (sqkm) under Basin. Indian States and Other Countries Water Resources Development and Management at Local Level 1 Burhidehing Brahmaputra 8730 Arunachal Pradesh-6265 n In a basin, there is a place for the whole range of structures - large to small, the latter has Basin Assam - 2465 a particularly important role in the north eastern region. 2 Kopili-Kalang Brahmaputra 20068 Assam-14872 n Renovation and modernization of tanks and other local water resources are to be Basin Meghalaya-5196 considered as priority task. The programme needs to be planned and implemented on a 3 Ranganadi Brahmaputra 2941 Arunachal Pradesh-2241 watershed basis, taking into account the comparative techno-economic feasibility of Basin Assam - 700 renovating existing tanks vis-à-vis construction of supplementary tanks, upstream and downstream. In Assam the wet lands (beels) be considered as potential resources. 123 124 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

4 Dikhow Brahmaputra 4022 Arunachal Pradesh-47 Assam - 928 23 Dhalewsari Barak Basin 4784 Assam - 750 Basin Nagaland- 3047 Mizoramd-4034 5 Puthimari Brahmaputra 1787 Assam-1191, 24 Subansiri Brahmaputra 37000 Tibet - 14000 Basin Bhutan- 596 Basin Assam - 1200 Arunachal Pradesh-21800 6 Dhansiri(S) Brahmaputra 10305 Assam - 4513 Basin Nagaland-5725 25 Gaurang Brahmaputra 1023 Assam-834 Basin Bhutan- 189 7 Pagladiya Brahmaputra 1674 Assam-1251 Basin Bhutan- 423 26 Gabharu Brahmaputra 296 Arunachal Pradesh-57 Basin Assam - 239 8 Noa-Nadi Brahmaputra 745 Assam-651 Basin Bhutan-94 27 Belsiri Brahmaputra 751 Arunachal Pradesh-170, Basin Assam - 581 9 Dikrong Brahmaputra 1528 Arunachal Basin Pradesh-1276 28 Bhogdoi Brahmaputra 2495 Assam - 1753 Assam - 252 Basin Nagaland-736 10 Jia-Bharali Brahmaputra 10289 ArunachalPradesh-9360 29 Gadadhar Brahmaputra 610 Assam Basin Assam - 929 Basin 11 Disang Brahmaputra 3890 Arunachal Pradesh- 30 Depota Brahmaputra 296 Assam Basin 1440, Assam-2067,Nagaland-383 Basin 12 Champamati Brahmaputra 1142 Assam-1005 31 Kulsi-Deosila Brahmaputra 3770 Assam-685 Bhutan- 137 Basin Meghalaya-3085 13 Na-Nai Brahmaputra 909 Assam-751, 32 Buroi Brahmaputra 791 Arunachal Pradesh-654 Basin Bhutan- 158 Basin Assam - 137 14 Jinari Brahmaputra 594 Assam-183 33 Dhansiri (N) Brahmaputra Basin 956 6 Arunachal Pradesh- Basin Meghalaya-411 231 Assam - 623, Bhutan - 102 15 Jiadhal Brahmaputra 1346 Arunachal Pradesh-306 34 Barnadi Brahmaputra 739 Assam - 612, Bhutan - 127 Basin Assam - 1040 Basin 16 Bharalu Brahmaputra 115 Assam-54 Meghalaya- 61 35 Brahmajan Brahmaputra 92 Arunachal Pradesh-25 Assam - 67 Basin Basin 17 Lohit Brahmaputra 29487 Tibet-15034 Arunachal 36 Dudhnoi-Krishnai Brahmaputra 1064 4 Assam-298, Meghalaya-766 Basin Pradesh-12286 Assam - 42167 Basin 18 Majuli (Island) Brahmaputra 800 Assam 37 Beki-Manas-Aie Brahmaputra 43497 Assam - 6828 Tibet Basin Basin & Bhutan - 36669 19 Jinjiram Brahmaputra 3467 Assam-975 38 Bargang Brahmaputra 550 Arunachal Pradesh-350 Basin Meghalaya-2492 Basin Assam - 200 20 Ghiladhari Brahmaputra 670 Arunachal Pradesh-51, Assam - 619 39 Tipkai Brahmaputra 1744 Assam-1572 Basin Basin Bhutan- 172 21 Moridhal Brahmaputra 929 Arunachal Pradesh- 40 Tangani Brahmaputra 237 Assam-191 basin 128, Assam - 801 Basin Bhutan -46 22 Jhanji Brahmaputra 1139 Assam - 316 Nagaland- 823 41 Sankosh Brahmaputra 10345 Assam - 849 Bhutan - Basin Source: Brahmaputra Board 125 126 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Examples of rent river basin organizations in India Climate Change Odisha Various studies on climate change have drawn the conclusion that both rainfall and temperatures are predicted to be more variable, with consequent higher incident of draughts In 2007, Government of Odisha has approved the formation of River Basin organisation and floods. The water demand in irrigated agriculture is likely to increase due to prolonged (RBO) to plan and monitor (oversee) all water related activities in river basins. The structure dry spells, scanty rain during crop growing stages and increased temperature. Shift in date of of RBO is a two-tier one with a Board and a Council. The board will be a professional body initial precipitation will also impact the date of sowing /planting and create pressure on the with responsibility to plan development of water resources in the basin and the Council will irrigation systems. The river basin planning will be a good strategy for responding to climate be a body of stake holders to deliberate on action plans put up by the Board and accord change impacts on Water resources are ecosystems of river basins. necessary approval. River basin managers take care of planning at individual river basins. Eleven river basin organizations for river basins namely Mahandi, Brahmani Baitarani, Capacity Development Subarnarekha, Budhabalanga and Jambhira, Rushikulya, Bahuda, Vansadhara, Nagabali, Water resource management requires a minimal level of capacity at all levels, including Indravati, Kolab are formed in Odisha. that of decentralized local governments. Functional community-level capacity builds Meghalaya resilience to hazards, and facilitates the use of knowledge and technologies, innovation and education, thereby creating a culture of safety and resilience at all levels. Local In 2011, Govt. of Meghalya has constituted a basin development council for initiating capacity development and training priorities should be expressed as a regional agenda, activities on IWRM and planning of proper water use by involving local communities and to enable many partners along with the research-to-development continuum, and to form different State departments. Meghalya basin development authority and district basin collaborations where consortia, alliances, networks, and individual organisations may all development units are important institutional setups in the basin planning approach in ?nd their place to both fund and bene?t from it. Regional training priorities are best Meghalaya. Govt. of India has supported such a innovative step taken by Meghalaya which expressed in terms of problems of water functions that need to be addressed locally but is first of its kind in the entire NE region. regional synergies are possible. Development of a community's ability to function in Ecosystem Management participatory processes is also an important part of capacity development. Consensus-building An eco system is a complex set of relationship among the living resources, habitats and should be based on dialogue amongst stakeholders. Jargon free terminology should be used residents of an area. It includes plants, trees, animals, fish, birds, water, soil and people. to facilitate comprehension by important stakeholders outside the water sector. Thus, each Every thing that thrives in an ecosystem depends on the other species and elements that are stakeholder group would have a comprehensive vision of basin issues. Preparing the part of the ecological community. If one part of the eco system is damaged or disappears it community to cope up of with the climate change induced impact on water resources should has an impact on every thing else. In the backdrop sustainability concept which is a core be addressed in the capacity development planning. principle in any programme, proper management of eco-system to derive ecosystem goods Suggestions and services and conserve bio-diversity is an important issue. The north eastern region is River basin organizations and institutional mechanisms are already in place in some states rich in flora, fauna, micro flora etc. Community bio-diversity committees which are local level of India. In Assam, formation of river basin organizations may be pursued that have institutions as per the bio-diversity conservation programme in India can be leveraged under multidisciplinary function and role. Under the basin organization all kinds of data about the the over all basin planning and development activities. basin, discharges in streams, sediment load, vegetation cover, watershed, irrigation, flood Ecosystem Goods and Services control projects, ground water potential and its utilization, fishery, wetlands, other Ecosystems provide a variety of goods and services upon which people depend. Ecosystem developmental projects using natural resources be collected and collated. Basin development goods include the "tangible, material products of ecosystem processes-food, construction plans to maximize productivity from the available water resources and also to minimize hazards material, medicinal plants-in addition to less tangible items like tourism and recreation, and due to flood and erosion may be formulated. Convergence of programmes of different genes from wild plants and animals that can be used to improve domestic species. Ecosystem Government departments and Panchayat Raj institutions to implement activities outlined in services, on the other hand, are generally "improvements in the condition or location of things the basin development plan is also emphasized. Basin level scientific studies may be initiated of value". These include things like the maintenance of hydrological cycles, cleaning air and that will build scientific and technical capacity in Assam. Basin level studies to predict climate water, the maintenance of oxygen in the atmosphere, crop pollination and even things like change impacts and coping up mechanism may be planned in future. beauty, inspiration and opportunities for research. While ecosystem goods have traditionally n n n been recognized to have economic value, ecosystem services tend to be taken for granted. 127 128 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Analysis of satellite data in conjunction with drainage, lithology, land use/ land cover and collateral data facilitate effective evaluation of geomorphological conditions and status of degraded lands. These data sets in the core of Geographical Information System (GIS) provide A Study onhe t Change Detection of Land Use/ an excellent means of spatial data analysis and interpretation. It also provides a powerful mechanism, not only to monitor degraded lands and environmental changes, but also permits Land Cover ofhe t Majuli Island of Assam analysis of information of other environmental variables (Reddy et al., 2002). In recent years, remote sensing has been emerging as a powerful tool for generating information which helps to evolve the optimum land use plan for sustainable development of Swapnali Barman an area. On the other hand, GIS helps to handle large volume of data and integration of Assistant Engineer, Water Resources variety of parameters in more efficient fashion. This has emerged as an essential tool for Department analyzing and graphically transferring knowledge about the earth resources (Burrough, 1986). M.K.Dutta S.P. Aggarwal Remote sensing and GIS techniques have been proved to be immense help in land cover Department of Civil Engineering, Indian Institute of Remote Sensing mapping (Khoram and John, 1991). Jorhat Engineering College Majuli is regarded as the largest river island of the world. The island is suffering from ABSTRACT: bankline erosion due to the erosive nature of the river Brahmaputra on its south and due to the river Subansiri on its north. Apart from the streambank erosion, the land use/land cover of Survey of India toposheet of 1975, IRS-1B LISSII geocoded data for 1998 and IRS-P6 the island is also changing gradually. In this study, an attempt has been made to determine LISS III data for 2008 were used for mapping of the landuse/landcover of the Majuli Island. the LULC changes that has been taken place in the island during the period from 1975 to Analysis of the LULC changes revealed that total grass land has declined by 22.62 % of the 1998 and then from 1998 to 2008. total area of the island. A reduction in fallow land (18.6%) is followed by decrease in areas of plantation (2.19%) and surface water bodies (0.16%). However, the area covered by settlement has increased by 1.47%. As the island is suffering predominantly from riverbank erosion, the analysis showed that, majority of fallow land and grassland was eroded by the river. The per cent area of total eroded area of different LULC classes in their descending order during 1975 to 2008 are, grassland (20.82 %) , fallow land (16.19 %) , settlement (4.06 %), surface water body (0.56%) and plantation (0.47%). 1. Introduction The term "land use" and "land cover" (LULC) are often used simultaneously to describe maps that provide information about the types of features found on the earth's surface (land cover) and the human activity that is associated with them (land use) (Shetty et al., 2005). Land use/land cover inventories are assuming increasing importance in various resource sectors like agricultural planning, settlement surveys, environmental studies and operational planning based on agro-climatic zones (Jayakumar et.al, 2003). Land is the most important natural resource, which embodies soil, water and associated flora and fauna involving the total ecosystem (Shamsudheen et al., 2005). The change in the state of the biosphere and bio-geochemical cycles are driven by heterogeneous changes in land use and continuation of those uses (Turner, 1995). The changes in land use/land cover due to natural and human activities can be observed using Survey of India (SOI) toposheets and remotely sensed data. The change is also critically linked to the intersection of natural and human influences on environmental change. Fig.1: Location map of the study area

129 130 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

2. Methodology LULC map of 1975 The Survey of India toposheets No. 83 F/5, F/6, F/9, F/13, I/4, I/8, J/1 and J/5 (Scale The LULC map of 1975 has been prepared from the Survey of India toposheet of 1975 1:50,000) of 1975 were georeferenced, mosaiced and used for preparation of base map. The (scale, 1:50,000). The area of the island in 1975 was 706.14 Km2. The majority of the total LULC map of the Majuli Island of 1975 was prepared from this toposheet. IRS-1B LISS-II area was covered by fallow land (50.86%) which was followed by grassland (30.24%), satellite imagery of 1998 and IRS-P6 LISS-III satellite imagery of 2008 were registered to the settlement (11.49%), water body (3.98%) and plantation (3.43%) respectively (Fig.2). base map using a set of Ground Control Points (GCPs) in ERDAS IMAGINE 9.1 software. These two satellite data were used to map the land use/land cover status during these two respective years. The land use/land cover map of 1975, 1998 and 2008 were prepared following on screen visual interpretation method by digitizing in ArcviewsGIS. Three attribute tables were created for the respective years to store the information such as area in square kilometer and type of the various land use/land cover categories. The different types of LULC digitized were fallow land, grassland, water body, settlement and plantation. Assessing landcover dynamics and change is important for assessment of its impact on various natural processes. Several methods, based on satellite remote sensing data are used to describe patterns and processes of landuse/landcover changes quantitatively. In this study, landuse change amplitude and landuse conversion matrices (Wang et al., 2007) were used to reveal the characteristics of landuse variations. The analytical method used is as follows: Measurement index, the variation amplitude Pi of a single land type is used to form the respective mathematical expression : Fig.2: Landuse/land cover map of 1975 with pie diagram showing per cent of total area covered by each landuse / landcover type Pi(%) = {(LUit1 - Luit0)/ LUit0}x100 LULC map of 1998 Where, Luit0 and LUit1 are the areas of ith landuse and landcover type at the beginning and at t respectively in the study region. The LULC map of 1998 has been prepared from the IRS-1B LISS II geocoded data of 1998. Here also, the majority of the total area was covered by fallow land (53.13%). The area In order to explore the internal conversion between different landuse classes, a landuse covered by the other classes in their descending order are, grassland (21.71%) > settlement change conversion matrix was implemented. The percentage of conversion loss or conversion (14.62%) > water body (6.12%) > plantation(4.42%) (Fig. 3). gain in relation to the total watershed area was calculated according to the following formulae:

P loss(i),j = {(a j,i - a i,j)/A} x 100

P gain(j),i = {(a i,j - a j,i)/A} x 100 Where, P loss(i), j is the percentage of total area taken by class i contributed to class j; similarly, P gain(j),i is the percentage of total area taken by class j contributed to class i. a i,j stands for the area of class i converted to class j, and a j,i stands for the area of class j converted to class i, A is the total study area. The calculations give the change that occurs in the region. 3. Results and Discussion Land use /land cover (LULC) maps were derived for the Majuli Island to represent the present and past LULC conditions and changes that have taken place over whole of the island in a span of thirty three years. Five major LULC types have been identified, namely, fallow land, grassland, water body, settlement and plantation. Changes in LULC between the Fig.3: Land use/land cover map of 1998 with pie diagram showing per cent of total area periods from 1975 to 1998 and from 1998 to 2008 have been presented here. covered by each landuse and landcover type

131 132 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

LULC map of 2008 The LULC map of 2008 has been prepared from the IRS-P6 LISS III data of 2008. The per cent of total area covered by each LULC type in their descending order are, fallow land (58.94%) > settlement (18.04%) > grassland (14.63%) > water body (5.23%) > plantation (3.17%) (Fig.4).

Table 1: Characteristics of Land use/land cover changes in Majuli Island (1975-2008)

Fig.4: Landuse/landcover map of 2008 with pie diagram showing per cent of total area covered by each landuse and landcover type Land use/land cover changes The change in each LULC class from 1975 to 2008 is illustrated clearly in Fig.5. Table1 to 4 Shows the internal conversion (matrices) of different LULC classes at different periods.

Table 2: Landuse conversion matrix and per cent change in classes (1975-1998). From 1975 to1998 % decrease in fallow land - 8.79 % decrease in grassland - 14.24 % increase in water body 0.96 % increase in settlement 0.85 % increase in plantation 1.13 % fallow land eroded -3.65 % grassland eroded -12.13 % water body eroded - 0.09 Fig.5: Landuse/cover change in Majuli Island from 1975 to 2008 % settlement eroded - 1.98 % plantation eroded - 0.24

133 134 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Table 4: Landuse conversion matrix and per cent change in classes (1975-2008). Table 3: Landuse conversion matrix and per cent change in classes (1998-2008).

From 1975 to 2008 From 1998 to 2008 % decrease in fallow land - 18.6 % decrease in fallow land - 10.79 % decrease in grassland - 22.62 % decrease in grassland - 8.24 % decrease in water body -0.16 % decrease in water body -1.13 % increase in settlement 1.47 % increase in settlement 0.67 % decrease in plantation - 2.19 % decrease in plantation - 2.19 % fallow land eroded -16.19 % fallow land eroded -10.07 % grassland eroded -20.82 % water body eroded - 0.56 % grassland eroded -8.22 % settlement eroded - 4.06 % water body eroded - 0.57 % plantation eroded - 0.47 % settlement eroded - 2.53 Analyzing LULC changes from 1975 to 2008, it may be observed that the total grass land % plantation eroded - 0.29 has declined by 22.62 % of the total area of the island. A reduction in fallow land (18.6%) is followed by decrease in areas of plantation (2.19%) and surface water bodies (0.16%). However, the area covered by settlement has increased by 1.47%. The use of land area covered by settlement is related with the population. The growth population is directly related to decrease in grassland, plantation and fallow land. So, the increase in settlement area can be attributed to the decrease in the reduction of area of grassland , plantation and fallow land in a span of 33 years.

135 136 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Variation amplitude from 1975 to 2008 showed reduced grassland accounting for 22.62% Acknowledgement: The authors thank Department of Science and Technology (DST), GOVT. of total change, 14.24% occurring from 1975 to 1998, and 8.24% from 1998 to 2008; reduced of India for supporting the research. We are grateful to Indian Institute of Remote Sensing fallow land area (18.6% of total change, 8.79 % occurring from 1975-1998, 10.79 % from (IIRS), Dehradun and Jorhat Engineering College (JEC), Assam for providing facilities to 1998-2008); decreased surface water body (0.16% of total change, 0.96 % from 1972-85 carry out the project works. and 1.13% between 1985-03); increased settlement (1.47% of total change, 0.85 % occurring References from 1975-98, 0.67% from 1998-2008). However, the area covered by surface water body and plantation was increased by 0.96% and 1.13% during 1975 to 1998 and was decreased Burrough, P.A., 1986. Principles of Geographical Information System for Land Resources by 1.13% and 2.19% during 1998 to 2008. As the island is suffering predominantly from Assessment. Oxford University Press, NewYork. riverbank erosion, the analysis showed that, majority of fallow land and grassland was eroded Jayakumar,S. and Arockiasamy, D.I, 2003. Land use/Land cover mapping and change by the river. The per cent area of total erosion of different LULC classes eroded by the river in detection in part of Eastern ghats of Tamilnadu using remote sensing and GIS. J. Indian their descending order during 1975 to 1998 are, grassland (12.13 %) > fallow land (5.65 %) Society of Remote Sensing, 31(4): 251-260. > settlement (1.98%)> plantation (0.24%) > surface water body (0.09%) and during 1998 to Khoram, S. and John, A.B., (1991. A regional assessment of land use/land cover types in 2008 are fallow land (10.07 %) > grassland (8.22 %) > >settlement (2.53%)> surface water Sicily with Landsat TM data, Int. J. Remote sensing, 12(1): 69-78. body (0.57%) > plantation (0.29%). Reddy, G.P.O., Maji, A.K., Srinivas, C.V. and Velayutham, M., 2002. Geomorphological analysis Taking the internal conversion of various LULC classes into account from 1975-98 and for inventory of degraded lands in a river basin of basaltic terrain using remote sensing and from 1998 to 2008 the major changes were the erosion of majority of the grass land and GIS. J. Indian Society of Remote Sensing, 30(1 & 2):15-31. fallow land by the rivers. From 1975 to 1998, changes found from fallow land to settlement and plantation. Similarly, from 1998 to 2008, major changes were from fallow land to settlement, Shamsudheen,M.,Dasog,G.S.and Tejaswini, N.B., 2005. Land use/Land cover mapping in grassland to settlement and plantation to settlement. The overall trend from 1975 to 2008 the coastal area of north Karnataka using remote sensing data. J. Indian Society of Remote saw changes from fallow land to settlement, grass land, water body, grassland to settlement, Sensing, 33(2):253-257. water body, plantation and plantation to settlement and fallow land. Shetty, A., Nandagiri, L., Thokchom, S. and Rajesh, M.V.S., 2005. Land use-Land cover Thus, the distribution of different land use/land cover types in 1975, 1998 and 2008 has mapping using satellite data for a forested watershed, Udupi district, Karnataka state, India. shown that the per cent positive change over the years was maximum for settlement. Other J. Indian Society of Remote Sensing, 33(2): 233-238. types of LULC showed only negative change. Turner, H.B.L., 1995. Linking the Natural and Social Sciences. The Land use/cover Change 4. Conclusion Core Project of IGBP. IGBP Newsletter, No.22. A detailed remote sensing based LULC change detection of the island during the period Wang, G.and Eltahir, E.A.B., 2007. Ecosystem dynamics and the Sahel Drought. GRL, 27: from 1975 to 1998 and from 1998 to 2008 reveals the following changes: 795-798 From 1975 to 2008, it can be concluded that, total grassland has declined by 22.62 %. A reduction in fallow land (18.6%) is followed by decrease in areas of plantation (2.19%) and surface water bodies (0.16%). However, the area covered by settlement has increased by n n n 1.47%. As the island is suffering predominantly from erosion, the analysis showed that the majority of the grassland and fallow land were eroded by the rivers. The per cent area of total erosion of different LULC classes eroded by the rivers in their descending order during 1975 to 2008 are, grassland (20.82%) > fallow land (16.19%) > settlement (4.06%) > surface water body (0.56%) > plantation (0.47%). Taking the internal conversion of various LULC classes into account, an overall trend from 1975 to 2008 saw changes from fallow land to settlement, grassland, water body, then, from grassland to settlement, water body, plantation and from plantation to settlement.

137 138 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Brahmaputra is one of the largest alluvial rivers of the world exhibiting an unusual degree of braiding. Width of the river (at bank full) within Assam varies from 6 km to 18 km except in nine reaches (nodal points) where it traverses through deep and narrow rocky throats. Brahmaputra Basin:houghts Some t Deonvelopment According to the Water Resource Department, Government of Assam (WRD, 2008), the Brahmaputra has shown a widening trend in Assamvalley during the last century: 4,000 km2 and Management of itsater W esourR ce in the 1920s, expanded to 5,000 km2 by the early 1970s, and 6,000 km2 in 2008. When the whole Yarlung Tsangpo-Siang-Brahmaputra-Jamuna stretch is considered, the drainage system is unique as the river runs in a completely opposite direction midway, i.e., in Tibet it Chandan Mahanta flows from west to east but after entering India, south of Tibet, it flows from east to west Professor, Department of Civil Engineering, through Assam, finally south bound in Bangladesh and traverses a series of unique ecosystems Indian Institute of Technology (IIT) Guwahati, of the Himalayas. Guwahati- 781039, India. Water Resources in the Brahmaputra Basin The water resource of the Northeastern India constitutes one-third of India's total (World ABSTRACT Bank, 2007a). An account of the quantified resource in the Brahmaputra Basin of Northeast India is summarized in Table 1. Brahmaputra River Basin is an ironic example of a basin remaining impoverished despite a colossal water resource. It is perhaps primarily due to absence of a holistic vision and Table 1. Summary of water resource of the Brahmaputra basin in Northeast India (Mahanta, supportive technology along with necessary institutional mechanism. The riparian northeastern 2006) states of India have so far failed to gain the productivity that is expected of such a vast Catchment area 194,880 km2 resource. Some basic factors that may be responsible are: (a) geographical isolation; (b) Water availability per capita 18,400 m3 partial or little water resource related research and development that can lead to basin scale Water availability per ha - scientific planning; (c) lack of a comprehensive blueprint developed through inter-state and Runoff per capita 21,060 m3 people consultation; (d) inadequate local decision making capacity and opportunity; (e) water 3 resource related institutional arrangements are bureaucratically complex and/or incomplete; Runoff per hectare 44,232 m and (f) disillusionment by almost all concerned of past water resource initiatives that failed to Annual surface water potential 1,869 km3 deliver. Long time-series of basin wide database, wider involvement and cooperation of water Utilizable surface water (including 690 km3 security sector, increased accountability by the departments, decentralization of decision Ganges and Meghna) making, inclusion of the floodplain community and above all, development and acceptance of Annual surface water availability 537 km3 an organized framework with sustainable mechanism and governance can definitely change 3 the current picture of water resource utilization as well as the region's economy. An effective Average annual runoff per ha 19,830 m /second umbrella organization at the basin level covering all riparian states and countries with a and per second sustainable management approach to facilitate and handle this exceptional water resource is Annual availability of water 44,232 m3 urgently needed to ensure a comprehensive solution that has eluded us so far. per hectare of cultivable area Introduction Wetlands Area covered by wetlands 223,704 ha Brahmaputra River Basin is undoubtedly the lifeline of the northeastern region of India. Wetland area usable for storage 102 km2 Brahmaputra basin falling within India constitutes a part of the Tsangpo-Siang-Brahmaputra- basins during floods Jamuna basin , which lies between latitude 250N and 320N and longitude 820E and 970E. The Groundwater drainage area of the basin is estimated as 580,000 km2, of which China, India, Bangladesh, _ and Bhutan share approximately 50%, 34%, 8% and 8% respectively. The percentages of Groundwater recharge rate drainage area among different states of India is approximately: Arunachal (42%), Assam Groundwater potential 26.55 km3/yr (36%), Meghalaya (6%), Nagaland (6%), Sikkim (4%) and West Bengal (6%) (Ojha et al. Annual utilizable groundwater per ha 27.9 m3 2004). 139 140 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Water demand form for execution of a long term water resource management project. The water resource Total water withdrawals 9.9 km3 management provisions often fall short of ensuring prior multi agency and stakeholder consultation as they are not designed to do so. Consequently, water resource is often managed Irrigation 8.0 km3 to meet specific and limited interests rather than holistically meeting multiple requirements 3 Domestic use 1.0 km appropriately and sustainably. Most of the projects are centralized, decision driven and without Industrial 0.9 km3 any effective consultation exercise with the target population and devoid of any inter-state - Not available. dialogue. Rainfall: The Monsoon rain accounts for 90% of the annual rainfall with an average between Successive waves of devastating floods are routine every year and have plagued the 2500 mm and 3200 mm (Purakit, 2004). Prolonged and heavy rainfall ranging from 2,480 economy, more particularly the agro-economy of the floodplain. The state has lost about mm in the Brahmaputra valley to 6,350 mm or more in the North Eastern hills is largely 7.4% of its land due to bank erosion and channel migration. concentrated during four to five monsoon months (WRD, 2004). The geologically youngest lithology of the Himalayas under the influence of intense rainfall Surface Water: About 8,251 km2 (10.5% of the total geographical area of Assam) is occupied and occasional seismicity, fill the main river and the tributaries with enormous amount of by surface water bodies, out of which; about 6,503 km2 is occupied by different river systems, sediment. High intensity rainfall, steep slopes of river and tributaries, landslides, slash-burn including the Brahmaputra, and 1,748 km2 by natural wetlands. The total surface water resource cultivation and gradual encroachment of forest areas have also contributed to high sediment of the State is estimated to be about 600 billion cubic meters (Draft State Water Policy of load. Interestingly, the sediment load - one of the highest in the world, which is arguably the Assam, 2007). most powerful driver of both inundation (by silting up river bed and channels) and bank erosion, has never been reckoned with sufficiently in case of planning and design of solutions. Ground Water: The annual replenishable Ground Water Resource of the state has been estimated to be 27 billion cubic meters and Net Annual Groundwater availability is 25 billion Clearly, flood control and erosion resistant infrastructure building have so far remained cubic meters (CGWB, 2009). often the only yet inadequate measures in seeking to provide solution. In almost all cases, these have treated the problem section of a river basin in isolation, without looking into the Hydropower: Due to topography and abundant surface water resource, the Northeastern overall consequences from a geo-environmental solution perspective. Some of the region is endowed with a hydropower potential of at least 66,000 megawatts (MW), which embankments were apparently constructed and planned even when there was insufficient represents about 40% of the national potential (World Bank, 2007b). There are a total of 897 model simulation or prototyping of potential solutions using adequate hydrological and hydro- small hydropower schemes in the Northeastern region with an installed capacity of 1487 meteorological and other required data. It cannot perhaps be ruled out that some solutions MW; along with 62 large schemes, with an installed capacity of 30,416 MW, distributed were designed on specifications that might have fallen short of the scale that was actually throughout the North-eastern region (SANDRP, 2002). The region has been acclaimed as required (WRD, 2005). The damages suffered by the existing embankment system during India's potential "future powerhouse" (Menon et al., 2003). The operating hydropower projects the floods of 1962, 1972, 1977, 1987, 1988, 1993, 1995, 1996, 1998, 2004 and 2012 indicated and projects under construction constitute 6% of the region's potential, as compared to an that the embankment system with the present condition - irrespective of the debate on their all-India 28%. effectiveness and apparently flawed execution - without constant maintenance, cannot provide Constraints of Development assured protection from medium and high flood and need improvement to ensure secured protection. Since there is no going back on what has been already put on place, future Naturally one must explore why in spite of a massive water resource, the riparian states of development, management and hazard mitigation have to be planned keeping in mind the Northeast India have failed to gain the expected prosperity out of it. Average per capita income present state of the river along with the existing embankments. It is understood that an in the Brahmaputra floodplains is 30 percent lower than the national average in India (Assam ambitious renovation project for the embankments is on the anvil. and Manipur being the lowest). Water resource development approaches practiced so far in the Brahmaputra Basin have divided the water sector amongst several government entities Effective Development and Management Options with fragmented responsibilities: Water Resource Department, Agriculture Department, Flood and bank erosion management Irrigation, Public Health Engineering, Fishery, Soil Conservation to name a few. Various responsibilities are also entrusted upon agencies and institutions, such as the Brahmaputra Over the years, short term and localized flood mitigation could only be generally achieved Board, Water and Land management Institute, NEC and so on. Amongst these, the than a sustained flood and erosion management while addressing the flood and bank erosion Brahmaputra Board was entrusted with development of Master Plans for the mainstream problem in the Brahmaputra Basin. Overall output has remained unsatisfactory in spite of Brahmaputra and all major tributaries. However, the Master Plans are perhaps not in a ready 141 142 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 investment of huge resources and effort. Since 2006-07, Water Resource Department has region is currently fraught with a range of technical and non-technical challenges, mainly due adopted the use of geo-synthetics, imported amphibian mini dredger and hydraulic driving to the threat to socio-economic resources, biodiversity and potential downstream and seismo- methods for bank protection, dredging of river bed and bamboo palisade works (Directorate tectonic impacts. The protest against large dams in the northeast has been primarily regarding of Economics and Statistics, Govt. of Assam, 2008). These, including the geo-tubes introduced the downstream impacts, with no sincere efforts visible to address the issues adequately. in 2009, are new technologies for Assam holding some promise provided these are The Environmental Impact Assessments (EIAs) reports accepted by the Ministry of administered appropriately supported by sufficient R&D and pre-planning. It has been Environment and Forest for the big dams of Arunachal Pradesh, (the Lower Subansiri, Kameng experienced that no structural measure alone is sufficient to manage the flood and erosion and Siang hydropower projects for instance) have left much to be desired (Menon et al., problems, and, a combination of several suitable measures often provide superior 2003). Community involvement in decision making, focus on critical environmental performance. Flood plain management, in terms of flood plain zoning, flood proofing, and conservation, safety of locations, availability of power grid system, international transmission flood forecasting can enhance communities' abilities to live "intelligently with floods". There routes are some of the major issues pertaining to hydropower. Clearly, any project in this is a strong need that the floodplain dwelling river bank community is very much part of the region before being implemented should ensure that elaborate technical investigations entire process of mitigation measures. Without a local ownership and proactive maintenance, covering all pertaining aspects are carried out to allay all apprehensions and putting in place safety and sustainability of any protection infrastructure will be in jeopardy. This has been fool proof mitigation measures of unavoidable yet reconcilable impacts including ensuring proved time and again - be it embankment, stone spurs, geobags, porcupines or simple that socio economic security, livelihood security, environmental security, water security and bamboo based porcupines or revetments. On the issue of bank failures, the critical role of food security is not jeopardized. Alternatives of development of small/mini/micro/pico hydel sediment morphology and the geotechnical aspect of bank erosion need particular attention. projects, wherever feasible, must be explored in a targeted manner, ensuring benefits of A preparedness plan for the perpetual and anticipated innundation problem is urgently required electrification of villages, job creation, monetary compensation including other priority activities besides flood shelter and scientifically designed community emergency platforms. These are like safety and livelihood assurance. In many instances, at local levels, these are being argued just a few examples and much introspection and in-depth deliberations are due for solutions as a better options and hence deserve careful examination, although in simple monetary to be robust and sustainable. terms, it may appear less profitable. Hydropower Adaptation to Climate Change Hydropower projects have become the most important focus of water resource development The most serious regional impact of climate change would be potential change in the river in the upper Brahmaputra Basin. By current norms, 12 percent of the annual power generated hydrology of the Brahmaputra valley, due to rapid glacial melt and regression of the Himalayan from the existing hydropower projects is earmarked for the states as "free power" (royalty glaciers (Tangri, 2003). The major glaciar fed rivers of North East India, having significant paid to the states for the use of their natural resources). Two potential projected benefits are impact on the environment and lives of the people in the Himalayan region are the Manas reduced flooding in the valley by flood cushioning, storage facilities in the hydropower reservoirs (31,080 km2), Subansiri (81,130 km2), Brahmaputra (256,928 km2), Dibang (12,950 km2), upstream, and substantial employment generated from the significant investment (more than and Lohit (20,720 km2) (Hasnain, 1999), besides a large network of other tributaries, streams Rs. 1000 billion). There are anticipated influence and implication on other sectors as well, and springs. such as service, transport, and tourism. The proposed Brahmaputra Valley Authority is Results from early greenhouse warming stimulations in MPI-ECHAm3 model experiments expected to be the institution to drive ahead most of the future water resource development suggests that mean annual surface runoff throughout the Tropical Asian region could increase mandates. The Authority will obviously have examples to be learned from similar River Basin by about 15% by the end of the century, with the greatest increase in Brahmaputra Basin and Organizations established for other large river basins including those in China such as the Indonesia (Lal, 1994). With the changing climatic scenario, there will be change in the pattern Yellow River Conservancy Commission. A major learning aspect will be the basin scale of runoff, discharge, and flow regime in all the major water sectors thereby increasing the risk sustainable development approach including accommodation of the downstream social and of flooding in the region. Again, the receding glacier trend can make the Brahmaputra a environmental implication of these projects. seasonal river along with the Ganga, Indus, and other glacier fed rivers in northern India NE hydropower initiative indeed requires useful analysis for net benefits considering both (IPCC 2007). tangible and intangible gain and losses. Embarking on any large hydropower project in the

143 144 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Considering the serious threat of climate change impacts on water quantity, quality and development of inland water transport, economic activity is projected to increase with sanitation, there is an urgent need of institutional mechanism and policy to initiate the mitigation generation of additional 27,000 jobs by 2020 (World Bank, 2007c). Overall projected rate of and adaptation mechanism in the Brahmaputra Basin. Institutional mechanisms and policies economic return on investments in inland water transport is around 15 percent. Cost-benefit need to be undertaken by departments like the Water Resource Department, Agriculture analysis, integration of water transport into overall development picture, increased input of Department, Health Department and such sectors in which climate change could mark its the private sector and the development of a structure for public-private partnerships, increased impact directly or indirectly. Focus should be given on short term actions for adaptation and cooperation with Bangladesh and local-level infrastructure for community water transport on mitigation. It is necessary to link climate change adaptation and mitigation strategies with the secondary rivers are the major issues needed to be addressed in order to get maximum socio - economic and institutional set up of the region which is inhabited by a multitude of benefit in a sustainable way from the inland waterways in the Brahmaputra in accordance ethnic minorities, tribes and clans and whose dependence on natural resources magnifies with international best practices. the risk they face due to climate change. Wetlands: As many as 3,513 wetlands have been identified in Assam valley alone by Assam Other water related development and management options Remote Sensing Application Centre (ARSAC). Wetlands play a fundamental role in conservation of biodiversity, production of fish and aquatic resources, flood control, Drinking water: With growing emphasis on using surface water as drinking water source, detoxification of the polluted water and ecological balance. But due to encroachment and there is dire need of comprehensive information system on water quality of the Brahmaputra cultivation in marginal areas, blockade of feeder channels, unscientific construction of Basin. Ground water of the basin is often acidic, turbid with high amount of Iron. Fluoride and engineered structures, release of industrial and urban wastes, wetlands in the Brahmaputra arsenic contamination in major parts of the basin has created threat to public health. It is time Basin is degrading rapidly. Administrative, socio-economic, and ecological measures must to seek alternatives before it is too late to cope with serious situation similar to Bangladesh. be put in place to stop degradation of wetlands and improve their productivity potential. A Augmentation of groundwater aquifers by surface water should be considered and investigated single management organization, banning of indiscriminate construction of infrastructures along with other feasible options along with ensuring source sustainability of surface water across wetlands, demarcation of wetland boundaries, removal of weeds on a regular basis, both for water security and safety. trapping of sediments from flowing in, restriction of releasing effluents from industries and Irrigation: The economy of the Brahmaputra Basin is predominantly agrarian. With massive regulation of liquid and solid waste discharged from municipal areas are some vital necessary amount of surface water supplemented by considerable ground water reserves, irrigation measures. can significantly help in making the region self-sufficient in agricultural production. Assessment Towards Renewed Policies of available groundwater for irrigation without lowering the water table to uneconomical levels, storage based irrigation projects, and particularly multi-purpose projects are clearly desired. Integrated Water Resources Management (IWRM) is recognized by many as the paradigm Strong coordination among various operations and groups, such as irrigation, agriculture, for establishing good water governance. IWRM can be considered for putting water resources Panchayat & rural development, and the farmers are the keys to irrigation development in of the Brahmaputra Basin on the recovery path. People's Republic of China is meeting its the Northeast region. The irrigation sector needs to do much better than the present and water challenges through IWRM in the Yellow River Basin. To get IWRM to work, three basic utilizing the water of the tributaries and the main Brahmaputra, it has the potential to change elements are proposed (ADB, 2005): the face of state like Assam. n Appropriate policies, participatory processes, and inter-state and international Transportation: There is significant potential for development of inland water transport for cooperation goods and passengers through the Brahmaputra, which has been already marked as the n Specified roles of institutions and stakeholder groups National Waterway 2. Shorter route of cargo transportation to the Northeast through the Sundarbans and Bangladesh via NW-2, viability during flood season, convenience in n Management tools, which involves regulation, monitoring and enforcement-all of which transportation of bulk commodities and large cargo used for industrial production and are ingredients of sound decision making. transportation of large scale construction materials are among the advantages of inland While looking at current scenarios in the Brahmaputra Basin, the following steps may be waterways as the main network of transportation of bulk goods in the region. Through fruitful in management of water resources and development in the Brahmaputra Basin:

145 146 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

1) Development and maintenance of knowledge base and special info. system There are at least 145 tribal communities of which 78 are large, each with a population of 2) Integrated numerical and physical modeling of water resource systems/ problems more than 5000. Indigenous people are unaware of critical issues. Adapting them to a changed water scenario, e.g., climate change, water security and so on remains a formidable task 3) Adoption of carefully chosen low impact (non-regressive) technologies indeed. 4) Equal importance on social, environmental and developmental issues To handle the vast water resource of the Brahmaputra Basin as a national asset, attention 5) Incorporation of climate change as additional layer of risk to be addressed should be given to ensure environmental flow maintenance, water rights and water usage, 6) Strong institutional mechanism and governance with judicious fund utilization avoiding conflict while doing so. The new voluntary program of U.S. Department of Agriculture (USDA) in active partnership with farmers to implement a range of land stewardship practices, There is undoubtedly very limited study and lack of authentic data to simulate including conservation tillage, nutrient management as part of their Conservation Reserve comprehensive scenarios. where data are available. Often these are classified, only partially Program (CRP) aims at improving the health of the Mississippi River Basin (Holdmeyer , available or not linked to policies. Documentation of technical knowledge and critical data by 2009). Such practices may be helpful in the Brahmaputra floodplains by recognizing the role different agencies and sharing of data are prerequisites for any scientific planning at a basin of the sediment, both as carrier and potential source of nutrients. The Government of Vietnam scale. Once simulation based dependable models and scenarios can be developed, the is targeting its water resources to generate exportable energy that will supply the country with issue of technology can be addressed at appropriate scale. Technological interventions may the capital needed to modernize its cities and alleviate poverty. Unique river basin organization be in terms of modification or new interventions which is adaptable to local conditions. set up by Quang Nam province, which is simple, practical and replicable, has become more To avoid water conflict in case of a trans-boundary river like the Brahmaputra, country participatory and innovative than its predecessors (Howell, 2007). Can something similar be level discussion and negotiation is essential for major projects, China has been facing considered for the Brahmaputra Basin? increasingly severe water scarcity, in the northern and southern part of the country due to Conclusion insufficient water resources to meet rising water consumption (Jiang, 2009) and there has been reports regarding possible diversion of the Brahmaputra from the Tibetan plateau. The Water resource issues are highly debatable and in the process often even the most obvious perceived threat by Bangladesh due to India's Tipaimukh Dam at Manipur and China's plan water pragmatism gets lost. Regional water resource management strategy formulated through to divert the Brahmaputra elucidates potential of transboundary conflicts over use of water involvement of all stakeholders can possibly change the current picture of water resource resource (SANDRP, 2002). There is a need that basin level umbrella organization takes such utilization in the Brahmaputra Basin and consequently the region's economy. Critical necessary issues to all riparian countries in order to seek a comprehensive agreement on the interventions include (a) wider inter disciplinary cooperation and contribution in water security; Brahmaputra. Strong bases of support among basin governments, high levels of authority (b) committed involvement and accountability by the agencies/ departments; (c) given through formal instruments like legislation and cooperation among members of the decentralization of decision making where community concerns are accommodated and (d) river basin organization are both prerequisites and ingredients for well functioning of any a highly motivated, competent and honest group of engineers, scientists and other River Basin Organization. For example, the success of the Murray-Darling Basin Commission professionals, who have the required knowledge, outlook, belief, passion and vision to achieve in Australia can in large part be attributed to its ministerial authority, the specific federal the goals that they set their eyes on. The State Water Policy, the State Water Council and the legislation supporting its operation, and united political backing. On the other hand, the absence Water Quality Task Force are some new initiatives holding promise for Assam although they of enforceable authority along with diverse political agendas weakens the operational capacity are yet to take off in strong footing. Assam needs to take promising steps now. Establishing of the Mekong River Commission (Mock, 2003). credible mechanisms to deliver on policy commitments and greater inclusion through equitably sharing short and long term benefits are the primary requirements for culturally and socially River basin management also requires strengthened mechanisms for transparency, public accepted economic benefits. It is essential to develop an organized framework to identify participation, and accountability to ensure that local concerns are incorporated into the and prioritize rewarding water resource investments; to embark on critical institutional reforms transboundary decision-making process and mechanism. The absence of such mechanism necessary for effective water governance and development and management of the region's may lead to inflexible or unenforceable basin-wide decisions that fail to engender local support vast water resources; to create a platform for communication between professionals, politicians or draw on local knowledge. Northeast India is the homeland of a large number of tribes. and the grassroots communities. The water organizations and institutions must work together

147 148 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013 and be able to create and manage an environment of incentives and disincentives that References encourage initiatives consistent with most beneficial water objectives. Failed policies/initiatives ADB. (2005). http://www.adb.org/Water/Actions/PRC/integrated-solutions.asp. of the past that benefitted small interest groups and continuously inflicted losses to the masses are not sustainable. Water security including long term protection from flood and erosion and Retrieved on 24.10.2009 other climate change induced hazards should be the norm for future. On a more practical Directorate of Economics and Statistics, Govt. of Assam. (2008). "Chapter-VI: Irrigation." note, to create opportunity to get engaged into serious sustainable water management planning Economic Survey, Assam 2007-2008, 38-40. and practices in the Brahmaputra Basin, the agencies involved with water resource Hasnain, S.I. (1999). "Himalayan Glaciers: Hydrology and Hydrochemistry." Allied development and management must explore ways of coming out of the vicious cycle of pre- flood construction, flood relief & rehabilitation, post-flood repair and restoration and next- Publ. Ltd., New Delhi. flood anticipation - all of which involve constant running after funds - in order to utilize its real Holdmeyer, F. (2009). "New Initative for Mississippi River Basin Headed Up by expertise in utilizing this nature-gifted exceptional legacy for making this entire basin one of the most prosperous in the world. There should not be any doubt that the Brahmaputra has NRCS." http://www.farmfutures.com/story.aspx?s=31825, Retrieved on 24.10.2009 all the potential to eventually churn out enough monetary gains to make every person living Howell, M. (2007). "Country Water Action: Viet Nam Next Generation RBO- in the basin lead a healthy and dignified life through honestly earned income out of sustainable livelihood nurtured by the uncontestable most vital resource of the future - pristine fresh Preparing for a Hydropower Future." http://www.adb.org/Water/Actions/VIE/next-gen- water. It should be aimed that the fund needed to manage Brahmaputra should be possible RBO.asp, Retrieved on 24.10.2009 from the earning out of its own resources. IPCC. (2007). "Summary for Policymaker." Climate Change 2007: Mitigation, Contribution of While short term mitigation, sometimes even on a fire-fighting or band-aid mode, cannot Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate be done away with, as far as long term solution of natural hazards and sustainable management Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge of natural resources like water is concerned, the whole world today has wisely chosen the University Press, Cambridge, United Kingdom and New York, NY, USA.. interdisciplinary path. To transform the Brahmaputra from a curse to boon, there is perhaps Jiang, Y. (2009). "China's water scarcity." Journal of Environmental Management, xxx, 1-12. no other means than addressing the challenge with all relevant disciplinary knowledge, Lal, M. (1994). "Water resources of the South Asian region in a warmer atmosphere." Advances expertise and traditional wisdom at our disposal. Starting from retrospectively analyzing where in Atmospheric Sciences, 11, 239-246. we might have gone wrong and lessons learned, we need comprehensive mapping and development of spatial and temporal knowledge base followed by hydrological, Mahanta, C., (2006). "Water Resources of the Northeast: State of the Knowledge Base." geomorphological, geotechnical, physical, chemical and material investigation of surface Background Paper 2, Study on Natural Resources, Water and the Environment Nexus for water, groundwater and sediments keeping a systemic perspective in view for the entire Development and Growth in Northeast India, Ministry of Development of North Eastern Region basin towards seeking future solutions. In doing so, we need help from all quarters. (MoDONER), India, and World Bank, Washington, D.C., U.S.A. Undoubtedly, the Brahmaputra is the most challenging river of the world and we need the Menon, M., Vagholikar, N., Kohli, K., and Fernandes, A. (2003). "Large Dams in the collective strength of local, national and international expertise to overcome the hazards and put this unparalleled resource into best service of humanity. With new threats like climate Northeast- A Bright Future?" http://oldcontent.northeastunlimited.com, Retrieved on change emerging, time is running out fast and instead of being called the proverbial ostrich 24.10.2009 with our heads buried in the sands of the Brahmaputra, we must brace ourselves to embark Mock, G. (2003). "Transboundary Environmental Governance: The Ebb and Flow of on this arduous but worthwhile pursuit for a better tomorrow. River Basin Organizations", http://earthtrends.wri.org/text/environmental-governance/feature- # Due to hurriedly preparing the article for the souvenir, some sources could not be attributed. The opinions 46.html, Retrieved on 24.10.2009 expressed are entirely of the author and should not be ascribed to any individual or institution. Ojha, C.S.P., and Singh, V.P. (2004). "Chapter 1: Introduction." The Brahmaputra Basin Water Resources, Kluwer Academic Publishers, Dordrecht, 1.

149 150 Proceedings Proceedings ASSAM WATER CONFERENCE - 2013 ASSAM WATER CONFERENCE - 2013

Purakit, B., (2004). "Chapter 3: Hydrometeorology." The Brahmaputra Basin Water Resources, Kluwer Academic Publishers, Dordrecht, 24. Need of Integrated Approach orf Mitigating SANDRP. (2002). "South Asia Network on Dams, River and People." http://www.narmada.org/sandrp/, Retrieved on 24.10.2009 Flood andosion Er oblemPr of Assam State Water Policy. (2007). "Draft state water policy (revised) 2007." Prepared by Civil Society Arup Kumar Sarma to Water Resource Department, Govt. of Assam. Professor and Head, Civil Engineering Tangri, A.K., (2003). "Impact of climate change on Himalayan Glaciers, Proceedings of Department Workshop on Water Resources." Coastal Zones and Human Health, NATCOM, New Delhi Indian Institute of Technology Guwahati Guwahati- 781039, India. TVA. (2009). Tennessee Valley Authority. http://www.tva.com/river/flood WRD. (2004). "The task force for flood management/ erosion control." Water Resource ABSTRACT Department , Government of Assam, India, 6-19. Rapid growth of population on the earth surface is forcing industrialization and urbanization, WRD. (2005). "Achievements under water resource sector 1996-2005." Water Resource conversion of forest area to agricultural/urban area and feeling up of low-lying areas to meet the resource need to support the increased population. All these ecological disturbances in Department, Government of Assam, India, 2. turn have caused increase in surface flow, reduction in infiltration, depletion of surface storage, WRD. (2008). "North Eastern Integrated Flood and Riverbank Management Project: Feasibility yield of more sediment from the upland and adverse climatic changes. Assam being a state Study (PPTA, Phase II)." Unpublished Report, Water Resource Department, Government of situated in a unique setup of river valley surrounded by hilly terrain, is worst affected and Assam, India. therefore, the floods and erosion is increasing at an intolerable pace. Looking into the nature's reaction, in the form of flood and erosion, to the present growth scenario it appears that this World Bank. (2007a). Development and Growth in Northeast India: The Natural Resources, valley is perhaps in the verge of crossing its population carrying capacity with present approach Water, and Environment Nexus- Strategy Report, 36397-IN, xv. of unplanned development. Therefore, a holistic approach is necessary for sustainable solution of the flood and erosion problem of this valley, which has wide natural and social diversity. World Bank. (2007b). Development and Growth in Northeast India: The Natural Resources, While short-term measures are necessary for immediate relief from flood and erosion, we Water, and Environment Nexus- Strategy Report, 36397-IN, 57. must make a long-term river basin plan for the entire basis. Mathematical model of the entire World Bank. (2007c). Development and Growth in Northeast India: The Natural Resources, basin is necessary for simulating flow and erosion. This will enable us to adopt protection Water, and Environment Nexus- Strategy Report, 36397-IN, 70. measures by evaluating various alternatives and by studying their impacts on the entire system and hence is an immediate need. For long-term solution, we must conceptualized the problem by considering all relevant aspects and solution strategies need to be prepared in an integrated n n n manner to have a win-win situation for all the states of the basin, so that it can become acceptable socially, politically and economically. Sorry part is that we are not finding a way acceptable to all for utilizing the huge water resources potential o