Government of Tamilnadu Water Resources Department HYDROLOGY PROJECT -II DECISION SUPPORT SYSTEM (DSS) with BASIN INFORMATION SYSTEM (BIS) VAIPPAR RIVER BASIN State Ground & Surface Water Resources Data Centre, PWD, Chennai-600113 1 Content iv Isohyetal maps - Above normal year (1979) 110 v Isohyetal maps - Summer Season 111 S No Subject Pages vi Isohyetal maps - Winter Season 112 1 Contents 2 vii Isohyetal maps - SouthWest Monsoon 113 2 Preface 3 viii Isohyetal maps - NorthEast Monsoon 114 3 Summary of Recomendations 4 ix Isohyetal maps - Nonmonsoon 115 4 Basin Information System 5 District Map 8 19 Dependable Rainfall 116 6 Block Map 9 20 Full Climatic Stations 7 Village Map 10 i Network of Full Climatic Stations map 118 8 Drainage Map 11 ii Theissen Polygon of Full Climatic Stations 119 9 Hydraulic Particulars of PWD & Union Tanks in 12 21 Evapotranspiration 120 13 sub-basins of Vaippar 22 Groundwater 10 Geology map 67 i Network of Observation wells map 124 11 Geomorphology map 68 ii Ground Water Level in Normal Rainfall Year Dec2011 - 125 12 Soil Map 69 Post-monsson 13 Topography(DEM) map 70 iii Ground Water Level in Normal Rainfall Year Dec2011 126 Pre-monsson 14 Landuse - Map 71 iv Deepest Ground Water Level in a Dry Year (May 2004) 127 15 Weightage of Landuse and Sub-surface Details 72 v Shallowest Ground Water Level in a Wet Year (Dec 2015) 128 16 Investigation Boreholes 23 Reservoirs and Anicuts map 129 i Network of Investigation Borehole map 73 24 Anicut Crest levels -DGPS 130 ii Lithology of Investigation boreholes map 74 25 River cross sections iii Lithology of Investigation boreholes -Details 77 i Location of River Crosssections map 133 17 Rainfall Ii Typical River Crosssection map 147 i Network of Raingauges stations map 104 iii River Crosssections DGPS survey details 148 ii Theissen Polygon of Raingauges map 105 26 Decision Support System iii Weightage of Theissen polygons of Rainaguges 106 i Tanks in 3 Cropping Pattern Zones 164 18 46 Year Rainfall Analysis ii Recommended Cropping Pattern for Rainfall predictions 167 i Isohyetal maps - 46 years annual average 107 iii Recommended Zones for Artificial Recharge Strucutres 173 ii Isohyetal maps - Below normal year (2016) 108 iii Isohyetal maps - Normal year (2011) 109 2 Preface 9) Network of tanks, both PWD and Panchayat Union together. 10) Sub-surface lithology showing the aquifers. The World Bank aided Hydrology Project-I was implemented in Tamilnadu at a cost of Rs.56.87 11) Cultivation pattern across the basin. during 1999 -2004. A well designed network of hydro-meteorological, hydrological and hydro-geological data observation stations were established across the state. Also a professional Hydrological Thus the Basin Information System is a very potential tool to the water managers of the Vaipar River Information System (HIS) was established to collect, process, store and disseminate the data on Basin. daily/hourly rainfall, hourly climatic data (Temperature, humidity, wind speed/direction, sun shine hours), The Decision Support System (DSS) is computer software that works on the Hydrological Model of a monthly groundwater levels and bi-annual water quality data. river basin. The hydrological model simulates all the constituent data like the GIS map based basin The World Bank aided Hydrology Project-II was implemented in Tamilnadu from 2006 to 2014, at a cost features, soil parameters and the driving forces like the rainfall to give the groundwater and of Rs.36.30. The objective of the project was to develop tools for practising Integrated Water Resources surfacewater as output. This model analyses the different scenarios of landuse pattern, available rainfall Management (IWRM) in the river basins of Tamilnadu. It was proposed to develop Decision Support and cropping pattern and gives out the resultant availability of groundwater and surfacewater. The DSS System (DSS) for Vaipar, Thamiraparaniar and Agniar basins. Among them the development of DSS for proposes to take decisions in the following 4 areas. the Vaipar river basin was taken-up on pilot basis. 1) For a given monsoon prediction, which part of the basin can go in for wet/dry crop? The DSS is a hydrological simulation model which replicates the features of a river basin into a set of 2) How much water for different sectors? How much from surfacewater and groundwater and Geographical Information System(GIS) based maps and supports in taking informed decisions on using when? the available water among competing demands like drinking, irrigation, industrial and environmental 3) Shall Tamilnadu invest in artificial Recharge Structures (ARS) in a particular location of the demands. This hydrological model essentially captures all the physical features of the river basin like basin? What are the impacts on the groundwater and surfacewater? rivers, canals, tanks, reservoirs, weirs, land use maps, raingauges, climatic stations, gauge-discharge 4) Whether to grant a groundwater abstraction permit? How much? stations, observation wells, pumping wells,lithology, geology and other details to the extend necessary Thus, the DSS is a potential tool in the hands of the basin manager to practice Integrate Water and feasible. All these features put together constitute a Basin Information System (BIS). Resources Management. This publication covers the Decision Support system (DSS) and Basin Information System for the This Decision Support System (DSS) comprising of the Basin Information System (BIS) is a product of Vaipar River Basin falling in the Virudhunagar, Thirunelveli, Sivaganga districts of Tamilnadu. the steadfast and dedicated works of the Engineers and Geo-scientists of the State Ground & Surface This BIS is a repository of valuable hydrological information of the Vaipar River Basin. It has the Water Resources Data Centre, WRD, Chennai, both at office and field together. All the stakeholders in following valuable information, the water resources of the Vaippar river basin are encouraged to make use of this product and their feedback are most welcome. 1) Digital Elevation Model containing the topographical information of elevation of every 10m x10m pixel. Chief Engineer, WRD 2) The crest level of the surplus weirs of all the tanks. State Ground & Surface Water Resources Data Centre, 3) The crest level of all the weirs. PWD, Tharamani, Chennai-600113 4) The cross sections of the entire drainage network of rivers and streams. 5) Annual average rainfall (46years) of 30 rainfall stations across the river basin. 6) Isohyetal maps of North East Monsoon (Oct-Dec), South-West Monsson (Jun-Sep) and Summer (Jan-May). 7) Piezometric heads of Above normal, Normal and below normal rainfall years. 8) Landuse map of the river basin including the ayacuts under the tanks. 3 Summary of Recommendations 6) The cross section data of the rivers and drainage network is essential for the hydrological model development. I will also be helpful in ascertaining the extent of encroachment on the river and to The DSS model for Vaipar river basin is helpful in the following two ways. take remedial measures. 1) It is a repository of the hydrological, meteorological and hydro-geological data of the river basin. Applications of the Decision Support System (DSS) 2) It helps take the following decisions in the vaipar River Basin. a. For a given monsoon prediction, which part of the basin can go in for wet/dry crop? The 46 years Annual Average Rainfall for the Vaipar river basin is 705mm/year. The predicted rainfall is b. How much water for different sectors? How much from surfacewater and groundwater classified into the following 5 types. and when? 1) Far Above Normal Rainfall, ( >20%) [>846mm]. c. Shall Tamilnadu invest in artificial Recharge Structures (ARS) in a particular location of 2) Above Normal Rainfall (5% to 20%) [740 to 846mm]. the basin? What are the impacts on the groundwater and surfacewater? 3) Normal Rainfall (+5% to -5%) [670 to 740mm]. d. Whether to grant a groundwater abstraction permit? How much? 4) Below Normal Rainfall (-5% to -20%) [564 to 670mm]. 5) Far Below Normal Rainfall (-<20%) [<564mm]. Applications of Basin Information System (BIS) A perusal of the kind of information made available in this Basin Information System goes to reveal that The Basin is sub-divided into the following 3 rainfall zones. it is a product of massive field survey fused with advanced GIS/Remote Sensing technology of first time a. Upper Zone in the state. To cite few applications of the BIS, b. Middle Zone c. Lower Zones 1) The Annual average rainfall hyetograph (46years) is a highly reliable data available for the calculation of yield available for formulation of new projects or upgrading existing projects like The following 3 landuses are there in each of the Zones. reservoirs, tanks and check dams. The Project Formulation Wing stands to gain. i. Tank Ayacut 2) The crest levels of the surplus weirs of the tanks, both PWD and Panchayat Union and weirs ii. Well Ayacut inside the Tank Ayacut were measured accurately with satellite based Differential Global Positioning System (DGPS) iii. Well Ayacut outside the Tank Ayacut for the first time in the state. These measurements are done in a short window of time and by a The north-east monsoon (Oct-Dec) is the predominant monsoon for Tamilnadu. At the start of every set of trained personnel and so the reliability is more. This level information is very crucial one monsoon, The India Meteorological Department (IMD) makes out a prediction of the ensuing monsoon, for the assessment of commandability while formulating irrigation schemes. Again, the Project like whether it is a normal one or above normal or below normal and to what extent. The 46 years Formulation Wing will be the beneficiary. normal rainfall for the Vaipar Basin is 705 mm as seen from the BIS. The DSS helps decide on a 3) The Digital Elevation Model (DEM) and the contours derived from it are useful for designing the suitable Cropping Pattern across the river basin for that monsoon.