GOVERNMENT OF TAMILNADU PUBLIC WORKS DEPARTMENT WATER RESOURCES DEPARTMENT

INSTITUTE OF HYDRAULICS AND HYDROLOGY POONDI - 602 023.

WATERSHED MANAGEMENT BOARD DIVISION

SEDIMENTATION STUDIES IN MARAVAKANDY (SECOND CAPACTTY SURVEy) Under DRIP

I.H.H. REPORT No: .1/2017

For official use only

Poondi - 602 023 February 201 7 GOVERNMENT OF TAMILNADU PTJBLIC WORKS DEPARTMENT WATER RESOTJRCES DEPARTMENT

INSTITUTE OF IIYDRAULICS AND ITYDROLOGY POONDT 602023.

WATERSHED MANAGEMENT BOARD DIYISION POLLACHI

SEDIMENTATION STT'DIES IN MARAVAKANDY RESERVOIR j ln Fr l?ri^ oltstl'\cL (sEcoND CAPACITY SURVEY) Under DRIP

I.H.H. REPORT No: 4/2017

For official use only

Poondi - 602 O23 February 2017

i OFFICERS INCHARGE OF THE STUDY

CHIEF ENGINEERS, P,W.D., W.R.D. Desigq Research and Conshuction Support" Chennai

ET.D.KHALEEL AEAMED, B.E., F.I.E., F.I.V. (i/c) ET.A.VENKATACHALAM, B.E, (Hons).,llIBA., ET.RVUAYARAGHAVAN, M.E, (Struct),F.I.E.,tr I.V,

SPECI.AL CHIEF ENGINEER / DIRECTOR, P.W.D., W.R.D. Institute of Hydraulics & Hydrology, Poondi

Er.I(VALARMATHI, 8.E.,

EXECUTIVE ENGINEERS, P.W.D., W.R.D. Watershed Management Board, Pollachi

ET.M.GNANASEKA& 8.E.,

ET.S.PRABHAKARAN, B.E.,(Vc)

ASSISTANT EXECUTIVE ENGINEE& P.W.D., W.R.D. Watershed Management Board Sub Division, Udhagamandalam.

ET.P.ELAITG0VAI\, B.8.,

ASSISTANT ENGINEER, P.W.D., W.RD. Watershed Management Board Section, Udhagamandalam.

ET.I.SUBRAMAIYI, M.8., WATERSHED MANAGEMENT BOARD CONDUCTING SEDIMENTATION STUDIES IN MARAVAKANDY RESERVOIR IN ITILGIRIS DISTRICT ( sEcor{D CAPACTTY SURVEY ) Under DRIP z--

CONTENTS

Chapter Title Page No.

I SYNOPSIS I 1.0 GENERAL 2 II MARAVAKANDY RESERVOIR 9 2.0 Introduction I

2.1 Sources ofsediment 9 2.2 Economic Importance of Sedimentation analysis l0

2.3 Reservoir Sedimentation il 2.4 Control of Sedimentation t2 2.5 Objectives ofthe Study t2

III 3.0 GENERAL l3 3.1 Climate of The Nilgiris t3 3.2.0 Location of the Maravakandy Reservoir 17 3.2.1 Maravakandy Reservoir General t7 3.2.2 Description of l8

3.2.3 Salient Features of Maravakandy Reservoir l9 3.2.4 Rainfall 20 M.0 General - Sedimentation studies )) 4.1 Methodology 22 4.2.O Catchment Area map )a 4.2.1 Water spread area map 23

4.2.2 Reconnaissance survey 23 4.3. Topographic survey 24 4.4 Hydrographic survey to find out the present bed level 25 4.5 Collectio! of Soil Sample and their analysis 26 4.6 Preparation of Contour map 26

4.7 Computation of Capacity 26 4.8 Analysis of the Data 28 4.9 Sedimentation Rate 28 4.9.1 Depth Vs Capacrty Relationship 29 4.9.2 Trap Effrciency 29 4.9.3 Life of Reservoir 30

v CONCLUSION JJ

List ofPhotographs 35 List of Annexures 40

List of Figures 45 I

SYNOPSIS

The Capacity Survey has been taken up by Watershd \,I"!g€q:I B"-d 6A under Dam Rehabilitation Improvement Project @RIP) in Maravakandy \d#oi, in Nilgiris District, Tamilnadu in the year of 2015-2016. The object of this study is to assess the quantum of silt deposited, present capacity and useful life of the Reservoir. The result of this capacity survey is compared with that of the original data

during the construction in 1947.

This report narrates briefly about the need of the study, mahodology adopted

besides the hydraulic features and rain ll in detail. Preparation of the contour map and computation of the present capacity are clearly brought out in this report. The results are ar:fllyzdl for the sedimentation rate, Depth venus capacity relationship, Trap Effrciency and Useful life of reservoir.

The capacity of the reservoir as on 2016 is 0.835 M.cum as against the origrnal capacity (1947) 0.959M.cum. Total quantity of sediment de,posited in between 1947 and 2016 (69years) is 0.124 M.cum. The average ,"rr*,t#E1{oad isQ.009l7 )o,oo1?r M.cum / year. The average annual silting rate per SC.Km isQ,00l79lM.cum / year / sq.x-ilt av is carried over as per analysisq(Iarctr z0l6]rre rap efficiency of reservoir n the year 2orck#eu?lifi ot."r"*oir is estimated 101 years.".r*J*6, L CHAPTER I \' 1.0 General

\, The Watershed Management Board Division was formed in 1973 Vide G.OMs

,! No 857 PW Dept Dated 26 IN{ay 1973 to conduct sedimentation survey and watershed ! studies for the selected /Tanks in Tamilnadu. . From inception (1975), so far the Sedimentation and watershed studies for the following reservoirVtanks L had been completed.

I Phase (1975 to 1985) Estimate Rs39.00 Lakhs. (As per G.O.Ms.No.l704 PWD dated 26.11.1974\ \' l.Emerald Avalanche (I Capacity survey - NILGIRTs DISTRICT) \- 2.Kundha Reservoir (I & II Capacity survey - MLGTRIS DISTRTcT)

\- 3.Pegumbahalla Reservoir (I & II Capacity survey _ MLGIRTs DTsTRICT)

! 4.Pillur Reservoir (I Capacity survey - coTMBAToRE DISTRTcT) ! 5.UpperBhavani Reservoir (I Capacity survey _ MLGIRTs DTsTRICT) ! 6.KrishnagiriReservoi(I,il&Iil Capacity survey_xrusuNAcrRr DrsrRrcr) T.Sathanur Reservoir (I & II Capacity survey _ TTRT.TvANNAMALAT DrsT) \, 8.Vaigai Reservoir (I,[& ilI Capacity survey _ rHEM DrsrRrcr) 9. Reservoir (I & II Capacity survey - corMBAroRE DrsrRrcT) l0.Mettur Reservoir (I & II Capacity survey _ sALEM DrsTRrcr] ! I l.Manimuthar Reservoir (I Capacity survey - TTRT.JNELvELT DISTRTcT) \- l2.LowerBhavani Reservoir (III & tV Capacity survey _ ERoDE DrsTRrcT)

II Phase (1985 to 1997) Estimate Rs.255.00 Lakhs.

(As per G.O.Ms.No.925 PWD dated S.4.f9S6 Est.Rs.l26 lakhs &G.O.Ms.No. 25 PW (Rf) dated 8.1.1999, Revised Est. Rs.255 Lakhs) LAmaravathyReservoir(I & IlCapacity survey {oIMBAToRE DrsrRlcr) 2.Thirumoorthy Reservoir (I & II Capacity survey - corMBAroRE DrsT) 3.Willingdon Reservoir (I & II Capacity survey - cuDDALoRE DrsrRrcr) 4. (I Capacity survey - DrNDrcuL DrsTRrcr) S.Barur Tank (I Capacity survey - KRTsHNAGIRT DrsrRlcr) 6.Parson Valley Reservoir (I & II Capacity survey - NrLGrRrs DrsrRrcT) 7. (I Capacity survey - MLGrus DrsTRrcr) 3

8.Ponnaniar Reservoir (I & II Capacity survey - TRICIry DISTRICT) 9.Kaveripakkam Tank (I & II Capacity suwey - vELLoRE DISTRICT) l0.Porthimund Reservoir 0 & n Capacity survey - MLGIRIS DISTRICT) I l.Uppar Reservoir (I & II Capacity survey - ERoDE DISTRICT) l2. (I & II Capacity survey - KAI.ryAKUMARI DISTRICT) l3.Manjalar Reservoir (I & II Capacity survey - THEM DISTRICT) l4.Mukurthy Reservoir (I Capacity survey - MLGIRIS DISTRIcT) l5.Perunchani Reservoir (I Capacity survey - KANYAKLJMARI DISTRICT) l6.Veeranam tank (I Capacity survey - cUDDALoRE DISTRIcT) l T.Wallajah Tank (I Capacity survey -cIJDDALoRE DtsrRICr) III Phase (1997 to 2001) Estimate Rs.25.00 Lakhs under WRCP (Part I) (As per G.O.Ms.No.347 PW(Rl)Dept. dated 19.06.1997) l.Varathamanadi Reservoir (I Capacity suwey - DINDIGUL DISTRICT) 2.Glenmorgan Reservoir (I Capacity survey - NILcIRIS DISTRICT) 3.Maruthanadhi Reservoir (I Capacity survey -'rHENI DISTRICT) 4.Chittar - I Reservoir (I Capacity survey - KANvAKUMART DISTRICT) 5.Perumal Tank (I Capacity survey - cLIDDALoRE DIsrRIcr) 6.Chittar - II Resewoir (I Capacity survey - KAI.IvAKUMARI DIsrRIcr) T.Palar-Porandalar Reservoir(I Capacity survey - DINDIcLIL DISTRICT) 8. Reservoir (I Capacity survey - NILGIRIS DISTRICT) 9. (As per G.O.Ms.No.56 PW(RI)Dept. dated 6.2.1998 for Rs.l .90 lakhs) (I Capacity survey - TIRUvALLLUR DISTRIcT)

\- IV Phase (2001 to 2003) Estimate Rs.lE.00 Lakhs under WRCP @art II) \, (As per G.O.Ms.No.103 PW(Rf)Dept. dated 1.3.2002) \- l.Kudhiraiyar Reservoir (I Capacity survey - DINDIGUL DISTRICT) . 2.Kamarajsagar Reservoir (I Capacity survey - NILGIRIS DISTRICT) \- 3.Parappalar Reservoir (I Capacity survey - DrNDrcuL DrsrRlcr) 4.Gadana Reservoir (I Capacity survey - TIRUNELvELT DrsrRrcr) 5.Gomuki Reservoir (I Capacity survey - cT.JDDALoRE DISTRTcT) From the inception year of 1975 up to 1996, Central and State funds were \' providedfortheabovestudies.For3rd&4th Phaseduringthe year1997 to2003,the

\- above sfudies for 14 reservoirs were conducted under Water Resources Consolidation

\- Project (WRCP) aided by World Bank vide G.O. Ms. No.347 PW (R1) Dept dated ! 19.06.1997 WRCP (Part-l). ]: V Phase (2003 to 2007) Estimate Rs.80.00 Lakhs L (As per G.O.Ms.No.645 Pw@l)Dept. dated 5.12.2003) l.Kadamba Tank (I Capacity & Watershed study- TU-ncoRrN DISTRICT)

2.Manimuthar Reservoir (III Capacity- TIRLINELvELI DISTRICT)

3.Maravakandi Reservoir (I Capacity & Watershed study- I.ILGIPJS DISTRICT) 4.Mukkurthi Reservoir Reservoir (II Capacity - NILcIRIS DISTRICT) \- 5.Maduranthagam Tank (I Capacity&Watershed study- cHENGULPATTu DISr) \' 6.Sathanur Reservoir (III Capacity - TIRLJVANNAMALAI DISTRICT) \, T.Kodaganar Reservoir (I Capacity & Watershed study - Dn IDIGUL DISTRICT) \, 8.Mettur Reservoir (III Capacity by Conventional - sarru DISTRICT) ! 9.Aliyar Reservoir (III Capacity- DISTRICT) v l0.Amaravathi Reservoir (III Capacity- ) l l.Krishnagiri Reservoir ([V Capacity - KRISHNAcIRI DISTRICT) v The above studies for all the Reservoirs/Tenks were completed. For Sathanur Reservoir-IBS survey completed upto +21 1.98M (FNL+222.20)

VI Phase (2007 to 30.09.2009) Estimate Rs.34.00 Lakhs s The following six reservoirs had been taken for Sedimentation survey and

! watershed studies at an estimated amount of Rs.34 Lakhs as per the G.O.(2D) No.29

\- PW (R1) Dept dated I I -07-2008 for 2007-2009. The proposal contains Sedimentation \, survey and Watershed Studies for selected five Reservoirs by conventional method \, and by Remote Sensing for Sathanur Reservoir. \, LMoyar Reservoir (instead of Pillur Reservoir) (I Capacity Survey - NILGruS DISTRICT) 2.Thirumurthy Reservoir (III capacity Survey - con mAToRE DISTRIcT) 3.Manjalar Reservoir (III Capacity Survey - THEM DISTRICT) \- 4.Pechiparai Reservoir (III Capacity Survey - TawAKUMARI DISTRIcT) \- 5.Veedur Reservoir (I Capacity Survey - vtLLupLJRAM DISTRICT) 5

6.Sathanur Reservoir(IllcapacitysurveybyRemote sensing - TIRWAI{NAIrvltr{LAI DISTRICT) Due to non completion of sedimentation survey for the above reservoirs within the stipulated time that is 3l-03-2009, the Govemment approved the extension of time upto 30-09-2009 vide in G.O. (D) No.229 PW (Rl) Dept dated 22-06-2009. The above works had been completed on 30-09-2009 in all respects, except Sathanur Reservoir.

VII Phase (From 01.10.2009 to 31.03.2011) Estimate Rs.26.50 Lakhs The following six reservoirs was taken for sedimentation survey and watershed

studies at an estimate cost of Rs.26.50 Lakhs as per G.O.Ms.No.l8 PW (R2) Dept. dated 20.01.2010 during 2009-201 I (01.10.09 to 3l.03.201 l)

l.Varattupallam reservoir (I Capacity survey - ERoDE DISTRICT) 2.Pykara dam (II Capacity survey - NILGIRIS DISTRICT) 3.Maruthanathi reservoir (II Capacity survey - DINDIGUL DISTRIcT) 4.Chittar II reservoir (II Capacity survey - KANvAKUMARI or(rmcry ' ' 5.vaniar reservoir (I capacity surv", @rsrRrcr) *at"rc+?a-' 6. Sathanur Reservoir (Remote sensing - III Capacity - rrnuvANNAMAI AI DIST All the above works had been completed including the Sedimentation study in Sathanur Reservoir through Remote Sensing Technique which was taken up by Maharastra Engineering Research Institute, Nashik.

\' During this period, additionally sedimentation studies for three more reservoirs

\, were conducted under DRIP as per G.O.Ms.No.88 PW (I.Spl) Dept. dated 15.03.2010, \, estimate cost of Rs.75.00 Lakhs. The reservoirs are Sathaiyar reservoir in Madurai \- district, AdavinainarKoil reservoir in Thirunelveli district and Gunderipallam \_ ./ reservoir in Erode district. The above works were completed. /U9 .- @n"." 1f"om 01.04.11 to 31.03.2013) Estimate cost of Rs35.00 lakhs \J During 27th Board Meeting the following six reservoirs were suggested for \- '/ conducting sedimentation and watershed studies during the year 2011-2013 and in 28th WSMB meeting the following six reservoirs had been approved for the year 2011-2013. 6

I .Kudhiraiyaru Reservoir 2.Vembakottai Reservoir (I Capacity survey - \TIRUDUNAGAR DISTRICT) 3.Perunchani Reservoir (II Capacity survey - KANYAKUMARI DISTRIcT) 4.Manimukthanathi Reservoir (I Capacity survey - VILLUPI.JRAM DISTRICT) S.Glenmargan Reservoir (II Capacrty survey - NILGIRIS DISTRICT) 6.Mettur Reservoir @ MDDL (By Remote Sensing - satru DISTRIcT) The Administrative Sanction for the above studies had been obtained from the Government vide G.O.Ms.No.23 PW(RI) Department dated 19.01.2011 for Rs.35.00 Lakhs The Chief Engineer (DR&CS) inspected the Kuthiraiyaru Reservoir on 29.01.201I and 30.01.2011 and instnrcted to identiff an alternate Reservoir instead of Kuthiraiyaru Reservoir since the rate of siltation in the Reservoir was very less and also the sedimentation study work was completed only in 2003. The Chief Engineer (DR&CS) inspected and selected Perumpallam Reservoir in SathiyamangalamTaluk,

Erode District for studies instead of Kuthiraiyaru Reservoir. Further the Chairman, Cauvery Technical Cell advised not to take up the Mettur Reservoir at MDDL sedimentation study work since it lies within the interstate problem. Hence it was proposed to take up Nagavathi Reservoir and Thoppaiyar reservoir in Dharmapuri District instead of Mettur Reservoir work. The proposal for the same had been approved by the Chairman, WSMB in the 29th WSMB Board Meeting held on 14.10.2011 and revised Government Order for the change of Reservoirs, Perumpallam Reservoir instead of Kuthiraiyaru Reservoir, Nagavathi and Thoppaiyar Reservoirs instead of Mettur Reservoir at MDDL had been issued by the

Govemment vide G.O.Ms.No. I 87 PW(RI ) departrnent dated 26.03.20 I 2. All the above works were completed. 9@hase - DRIP WORKS 208-2014 Estimate cost of Rs.E5.00 lakhs In the Government order M.S.No:73 Pubilc Works (I.Spl.l) Dept.

date:23.05.20 I 3 had accorded administrative sanction for conducting sedimentation study in l0 WRD under DRIP during the year 2013-14, at an estimated cost of Rs 85.00 Lakhs. $rr!5squently in the G.O. (M.S) No:48 Pubilc Works (I.Spl.l) Dept

dated 25.02.2014, certain amendments had been issued substituting l0 WRD Dams as 7

8 WRD and 2 TANGEDCO Dams (Glenmorgan (Kariappa) and Pillur Dams) and replacing the by Poigaiyar Dam in the WRD Dams list.

l.Parambikkulam Dam (I Capacity survey- rATAGHAT DISTRICT)

2.Thunakkadavu Dam ( l Capacity survey - PALAGHAT DISTRICT) 3.Pillur Dam (II Capacity survey - coIMBAToRE DISTRICT) 4.Glemorgan Dam (Kariappa) (I Capacity survey- NILGIRIS DISTRICT) S.Anaimadaw Dam (I Capacity survey - sALEM DISTRICT) 6.Pambar Dam (I Capacity survey- KRISHNAGIRI DISTRICT)

T.PilawkkalPeriyar Dam (I Capacity survey- vIRUDUNAGAR DISTRICT)

8.Anaikuttam Dam (I Capacity survey - VIRLTDUNAGAR DISTRICT) 9.Pechiparai Dam (IV Capacity Survey - KANYAKTJMARI DISTRICT) l0.Poigaiyar Dam (I Capacity Survey- KANvAKLTMARI DISTRICT) 4 Al1 the above works were completed. hase - DRIP WORKS 2014-2015. Estimate cost of Rs.58.00 lakhs @ The Empowered Committee Meeting for Dam Rehabilitation and Improvement Project (DRIP) was held on 08.10.2014. In this meeting the proposal for conducting Sedimentation Studies in l0 Dams ( 8 WRD + 2 TANGEDCO dams -KundhaPallam

and Pegumbahallah Dam) under Dam Rehabilitation and Improvement Project for the Year 2014-15 for an estimate cost of Rs.58.00 Lakhs was placed and got approved. The Government had accorded the administrative sanction for the above proposal for Rs.58.00 Lakhs vide G.O. (MS) No.253 Public works (I.spl 1) Dept. Dated: 18.12.2014 for the following 10 Dams. Based on the above G.O.'s Sedimentation

study for the following dams taken up in the year 2014-15.

l.Sholaiyar Dam (I Capacity Survey- coIMBAToRE DISTRICT)

2.Peruvarippallam Dam (I Capacity Survey- PALAcHAT DISTRICT)

3.KundhaPallam Dam (III Capacity Survey- NILGIRIS DISTRICT)

4.Pegumbahallah Dam (III Capacity Survey- coIMBAToRE DISTRICT)

5.Thumbalahalli Dam (I Capacity Survey- DHARMAPURI DISTRICT)

6.Kesarigulihalla Dam (I Capacity Survey- DHARMAPLru DISTRICT)

T.Golwarpatti Dam (I Capacity survey - vIRUDUNAGAR DISTRICT)

8.PilavakkalKovilar Dam (I Capacity survey - vIRUDt NAcAR DISTRIcT) 9.Nambiyar Dam (I Capacity survey - TIRUNELVELI DISTRICT) 8

lO.Vadakupachaiyar Dam (I Capacity survey - TIRUNELvELI DISTRICT) Thus Sedimentation study for Sholaiyar and Peruvarippallam dams were executed by Pollachi sub division. Accordingly this report is prepared for sedimentation studies conducted in Peruvarippallam Dam. /X.Ytr"." - DRIP WORKS 2015-2016. Estimate cost of Rs.45.00 lakhs The Empowered Committee Meeting for Dam Rehabilitation and Improvement Project (DNP) was held on 13.07.2015. In this meeting the proposal for conducting Sedimentation Studies in l1 Dams ( 8 WRD + 3 TANGEDCO ) dams under Dam Rehabilitation and Improvernent Project for the Year 2015-16 for an estimate cost of Rs.45.00 Lakhs was placed and got approved. The Govemment had accorded the administrative sanction for the above proposal for Rs.45.00 Lakhs vide G.O. (MS) No.20l Public works (WRl) Dept. Dated: 5.11.2015 for the following 11 Dams. Based on the above G.O.'s Sedimentation study for the following dams taken up in

the year 2015-16.

l.LowerNirar Dam (I Capacity survey - coIMBAToRE DISTRICT) 2.Maravakandy Dam (I Capacity survey - MLcrus DISTRIcT) 3.Maravakandi Dam (II Capacity survey - NILGIRIS DISTRICT) 4.Kamarajsagar Dam (II Capacity survey - NILGIRIS DISTRICT) 5.Chinnar Dam (I Capacity survey - DHARMAPLJRI DISTRIcT) 6. Sothuparai Dam (I Capacity survey - sALEM DISTRICT) T.Kullursandai Dam (I Capacity survey - VIRUDLJNAGAR DISTRICT) S.Ramanadhi Dam (I Capacity survey - TIRLTNELVELI DISTRICT) 9.Karuppanadhi Dam (l Capacity survey - TIRLJNELvELI DISTRICT) l0.Gundar Dam (I Capacity survey - TIRUNELvELI DISTRICT)

. -fk l- \...^.- I - \ '"' z!!r,"{,-; 5,r t. :. (F-r A. , ' ) *..,19,o or.,, t-.; & a.hl i :-, . lr-- A!',-t \.r, , \ -t-- v'4 I ,,,! r I '\ h [.,, v., >j C.:, ).rr.L.l 9

M AIL{V AIL{NDY RESERVOIR CHAPTERII 2.0 Introduction Water is one of the most valuable natural resources. The rapid growth of uncontrolled population and the development activities, both domestic and Industrial, throughout the world, have put tremendous pressure on the development and management of water resources. [n our country, the economic development of various sectors is dependent upon the indispensable water resources development. The

Water Resources of a country mainly depends on the rainfall, which is most erratic in nature. In the state of the surface and ground water is being totally harvested for the purpose of agriculture, domestic and industrial uses. This leads to chronic water crisis due to increased use of water for purposes, industrial and domestic needs of the increasing population. Most of the dams constructed in Tamil Nadu, are several years ago and due to natural process of erosion in the catchment area, movement of sediments deposits in various parts of the reservoir has reduced the storage capacity of the reservoir. Reduction in the storage capacity beyond a limit prevents the reservoir from fulfillment of the purpose for which it is designed. Periodical capacity surveys of reservoir helps in assessing the rate of sedimentation and reduction in storage capacity. This information is necessary not only for efficient managernent of the reservoir, but also helps in taking a decision about treatment of catchment area, if the rate of siltation is excessive. Periodical capacity surveys of reservoirs in a basin are also necessary to arrive at a realistic sedimentation index for planning of future reservoir projects in the basin and also to know how to use the available water in a better manner.

2.1 Sources of Sediments

The principal sources of sediments are as follows,

l. Deforestation 2. Excessive erosion in the catchment 3. Disposal of industrial and public wastes 1o

4. Farming 5. Channeli sation works 6. Human activities 7. Land development, highways, and mining

2.2 Economic Importance of Sedimentation analysis

The dynamic features like suspended sediment and its distribution concentration, water spread, density currents, aquatic vegetation, etc. are important parameters for multi-purpose river valley projects. These parameters have a bearing on the life of the reservoir and storage capacity due to the deposition of the transported bed-load, suspended load and wash load, which ultimately cause serious economic and social losses. The hazards like siltation in the man-made reservoir are of great concem because sometimes it affects the engineering structures also. Sediments in the reservoir degrade the water quality and may reduce the capacity for power generation. On the other hand, there may be improvement in the water quality downstream due to the sediments trapped in a reservoir and found economical for irrigation. The turbidity of the stored water in a reservoir also hinders recreational activities, municipal and industrial uses and fisheries. Another important aspect of reservoir sedimentation is formation of delta at the foreshore area of the reservoir, which ultimately affects upstream backwater and inundated lands.

A storage or conservation reservoir retains water during high floods for the use

in lean season. Sediment distribution and deposition within the reservoir gives an idea

to the planners, about the available assured adequate water supply.

The main sources of sediment are the erosion or washed up soil Ilom watershed of the river/tributaries, abrasion and land sliding of the shores. Sediments, in many :[eas are choking the streams, frlling in lakeV reservoirs/ponds/ canalV drainage ditchev harbours and burying vegetations. The monitoring of these parameters is essential. In the case of a very large reservoir, the trap efficiency of

these transported materials is near about 100 percent because very few particles can

pass the dam. The trap effrciency of the reservoir decreases with time due to reduction 11 in the reservoir capacity because of sedimentation. Reservoir operation plays an important role in the process of sedimentation. 23 Reservoir Sedimentation

The schematic diagram of sedimentation deposit in a reservoir is shown in the below figure. The process of sediment deposit in reservoirs takes place where the course particles with highest unit mass are deposited first and finest particles with low uoit mass are deposited at later. This leads to the segregation of sediments of different sizes and densrty. The grain size, its unit mass and shape influence the mobility and the settling capacity. The variation in the sizes of the deposited materials in the reservoirs also depends on the climate, drainage area and geology of the arealregion. The density of water in the reservoir is heterogeneous. The coarser particles mainly, gravel, boulder and partly sand move as bed load and form delta at relatively short distance from the estuary. This delta extends to the point where the maximum water level intercepts the original river bed.

Turbid inflow _-__| water surface o ^ - s s\ toosoo ss q s -"i-**""I*, / - 1 Sluice ways l-.-"-l Lake bed ------| -----,> Density current

Fine sediments

The seasonal changes in the runoff, cause the formation of multi-delta. The bottom sediments, which consist of finer particles, are deposited throughout the reservoir. The finest particles (silt, clay, colloids) often get flocculated and affected by dynamic viscosity of water. These particles sink to the bottom very slowly. They have a tendency to form density currents, which are generally moving towards spillways,

turbines and outlets. In many reservoirs, sediment -laden inflow may move through 12 the pool as a density current or layer of water with a density slightly different from that of the main body of the reservoir water. The density difference may result due to the sediments, dissolved minerals and temperature. The water of the density current does not mix readily with the reservoir water and maintains its identity for a considerable time because ofthe density differences. 2.4 Control of Sedimentation

Due to the multiple variables involved in reservoir sedimentation, no single control measure can be considered as the most effective. The measures, which can be employed to limit sedimentation and turbidity, are as under:

l. Soil and water conservation measures within the drainage basin, contour plowing, strip cropping, suitable farming practices, improvement of agriculture

land, construction of small dams/pondVterraceVcheck dams on gullies. 2. Revetment and vegetation cover 3. Evacuation of sediment 4. Reservoir shoreline protection 5. Stream bank and flood plain protection 6. Ridge plantation such as pasture development and reservoir shoreline protection. 2.5 Objectives ofthe Study The study has been programmed to achieve the following specific objectives:

l. To determine the present capacity ofthe reservoir 2. To determine annual storage loss 3. To find out the probable future life ofthe reservoir and 4. To periodically correct the stage vs capacity curve for eflicient operation of the reservoir. 13 , ,\-f) CHAPTER III

3.0 General

The Nilgiris is a part of the . Ooty the "Queen of Hill Stations", Coonoor 19 kms from Ooly and Kotagiri 31 kms from Ooty, are the three hill stations of this district. The district is located between 11"12' to ll'37' North latitude and between 76'30' to 76'55' East longitude. The district covers an area of 2452.50 sq. km: ..- 3.lClimate of The Nilgiris

Rainfall data from four stations over the period 1901-1950 were utilised and a perusal of the analysis shows that the average annual rainfall of the district is 1920 mm. It is minimum around Ootacamund (137 6.20 mm) in the eastern part of the district. It gradually increases towards west and attains a maxirmrm around Gudalur (2269.00 mm).

Pykara is one of the highest of south Indian streams originating in the Mukurti peak at an altitude of around 2400m ASL. It is the biggest stream in the Nilgiris

Plateau. The stream flows over a number of cascades and waterfalls that it provides a drop of about 1000m before it reaches the Pykara Dam at Glenmorgan. Downstream, Pykara joins the River Moyar and eventually River Cauvery through its tributary, the River Bhavani. ; The Pykara Hydroelectric Project SchemedE tf," first hydroelectric project that the state of Tamil Nadu (erstwhile Madras) launched and successfully implemented. The Project that was formally sanctioned during the British rule in 1929 was meant to generate and supply electricity for the industries in Coimbatore. Situated in the Nilgiris Plateau, the Pykara HP stands out as the highest in Asia and continue to be amongst the highest of hydroelectric projects in the world (source: Pell Frischmann Group and TNEB).

The Pykara flltimate Stage Hydroelectric Project (PUSHEP) that was completed during the beginning of the 21st century was formally inaugurated in September 2005. The power generation capacity of PUSHEP is 150 MW. The Pykara HP has been implemented in stages over a period of 75 years; PUSHEP being the final one. The spadework for the Project sta(ed in 1932. The first power-generating units were small with a capacity of 6.5 MW. Three such units were L4

installed in the powerhouse located at Glenmorgan taking advantage of the run-of- river water alone. In order to enhance the available flow, two regulating storages were added. 6!r These storages @tocatea at Mukurti (upstream) and Pykara (downstream). The additional flow thus achieved enabled the installation of more power generation

units. Subsequently, another storage dam was built across the Sandynallah stream. This reservoir was built to regulate and divert flows from a catchment of *fd a+ O@nto the Pykara Dam. The network of reservoin thus built helped achieve the set target of generating 70 MW of electricity.

In 1955, the Nilgiris Plateau experienced yet another major transformation due to the Kundah Hydroelectric Scheme. The Kundah HS led to the creation of Avalanche Dam (372m long; 57.66m high) and Emerald Dam (328.6m long; 65.72m high) around Portimund within the Kundah basin. A 733.77m long horseshoe-shaped tunnel that had the capacity to discharge of water connected the two dams. The }Rf;1ur."r Avalanche and Emerald streams (wen) tributaries that directly fed Pykara before the darhs were constructed.Two other dams were constructed across the tributaries of Pykara in 1965; Parson's Valley Dam (14.64ru;:iortimund Dam (10.66-d\r,^,+-.

These dams enhanced the volume of water that got diverted into the Kundah basin.

.- The Naduvattam Diversion Project completed in 1976 hamessed water from YIt ^ ^, la, the 12.82{g]tr {aduvattam basin that lies to the west of Pykara basin In order to augment further the power generation capacity of the Pykara HP, water was diverted y.$from the t2.916?one Valley and Melkodmund stream in the Nilgiris Plateau; both streams flowed between Pykara and Sandynallah. The huge volume of water thus diverted into the Pykara Dam necessitated the enlargement of the fore bay. The enlargement ofthe Pykara fore bay was completed in 1978-79.During the 1990s when the Pykara HP was in its final stage of implernentation (PUSI{EP) it had a well- established network of reservoirs that hamessed water from a catchment fed by Pykara, Sandynallah, Naduvattam, Melkodmund and Lone Valley streams (tributaries of River Moyar). The catchment has provided the gross storage necessary for making

PUStmP operational and generating the additional l50MW of electricity that was envisaged).During 1946-52, the Moyar Hydroelectric Scheme was implemented. The

Scheme was implemented using the tail water of the Pykara HP. The project is located w ar, 15 v d a dishce of l6lcm downhill of thc p:tlrra (Gleomorgro) pow€r stdiort" The Moyar ty HS also b€oefits by the wae that is diverted from tbe ltfarava&aody Dam Qocated \, notrth-€ast of lvlasinagudi) fuough a flumo chamel. At lvlaravakandy there is a mini- ! hydroelecrric scheire cqable ofp,roducing 2.6 MW of power C$,agi 1995). ! The Maravalmdy-Itfioyr flume chennel is 6.8llm long aod 10.86m wide. The ! Moyar ultimate Stagp Hy&oelcctic Project (MUSHEP) ttat was poposcd in 1995-- \, 1996 had envisaged the wid€ning of the flume chamd by anotr€r 2m. The chaonel v tbat is aound 2m @ had 19 hddgps across iB 3 wide (S-llm), 16 nanow (l-5m) aod 3 undogrounil passages. The vrious hydroelectric prcjects that wer€ iy v implemented since 1932 in the Nilgiris Plateau togrther established a 53tm n€ts,ort oftunnels (INO,2fi)7). v The follon ing reservoirs constitute &e Pytara gloup ofR€s€rvoirs. i, l. M*turthy w 2. Pykaa v 3. Karnaaj SaSE I 4. fvhavakmdy ly 5. Glenmoryan {., 5.Moya v v !, t/ \, t \, v t {v \. v v u v ti 16

The Nilgiri a history going back a good many centuries. Ifismt rs. Several sources cite thb reason as haze enveloping the area, while other sourc€s say it is because of the

'flower, which blooms wery twdlve years giving the ilopes a bluish tinge.

'In Nilgiris district the topogaphy is rolling ?rnd stetp. About 60 per cent of the cultivable land falls under the slopes ranging from 16 to 35 per cent. The altitude of t7

the Nilgiris results in a much cooler and wefter climate than the surrounding plains, so

the area is popular as a retreat from the summer heat. During summer the temperature

remains to the maximum of 25"C and reaches a minimum of lOoC. During winter the

temperature reaches a maximum of 20'C and a minimum of 0'C. Reports on the land

use pattern of Nilgris district was analysed as its contribution is vital from watershed management point of view The details are collected as per reports by Nalina et al ,..)n" (2014). The temporal changes ofland use and monitored using LISS I and LISS IIIpf Fs.. IRS lA and IRS-P6 satellites. Land use dynamics were identified using Maximum tSro likelihood classification under supervised classification technique. From the rernote Y-' sensing study, it is found that during the study period of 1990 to 2010, area of dense

forest increased by 27 .17%, forest plantation area decreased by 54.640/o. Conversion of forest plantation, Range land and open forest by agriculture and settlement leading to soil erosion and landslides. Tea plantation increased by 33.95% and agricultural

area for plantation of vegetables increased rapidly to 217 .56% in the mountain steep

area

3.2.0 Location of the Maravakandy Reservoir:

The Reservoir is situated in a fairly steep gorge near a place called Masinakudy is connected to Udhagamandalam by Moyar road and it is 36 KM away from it. The latitude and longitude I l'34' 5'N, 76"36'5"E respectively.

3.2.1 Maravakandy Reservoir General : Maravakandy Dam was constructed during 1947 across Avarahalla stream

(l1"34'29.28"N, 76'39'13.91'E) which is tributary to SIGUR RMR, act as a storage dam to Moyar Fore bay. It has a catchment of 20.72sq.km. This Reservoir has gross $aXupacity or o.es@i)The maximum water level and tull reservoir lerel(O-€ Vl rl , ..; 9l4.4m.The length of masonry $am is 60.72m.There is'/o gate to surplus, only .\ u- ;-^ spillway to a lenglh of 45.72m Ste scour vent of size 2.74mx2.74m. are there. This , reservior act as a storage Dam to Moyar Fore Bay. This water produces 750 IO h/ power and then the water goes to Moyar Fore Bay. The main inflow comes only in Singara power house. The main river in the free catchment is Avarahalla Stream. 18

3.2.2 Description of l)am

Maravakandy Dam was constructed during 1947 across Avarahalla stream which is tributary to SIGUR R[VER, act as a storage dam to Moyar Fore bay. It has a @^ catchment of 20.72sq.km. This Reservoir has gross capacity pf O.SS9G) Th" d.L'q\b,eril.. &.), \-/ maximum water level and full reservoir levela il 914.4m.The length of masonry dam is {\ . '1/ 60.72m.There is )G gate to surplus, only spillway is a length of 45.72m.One scour / vent of size 2.74nx2.74m.This reservior act as a storage Dam to Moyar Fore Bay.

This water produces 750 K. W power and then the water goes to Moyar Fore Bay. The main inflow comes only in Singara power house. The main rivers in the free catchment is Avarahalla Stream.

Bhavanl$aga

o 5 io l-T-l

r .. ' . ll":.' I --a"j, i)f 'r r-,1 r a\' !--1--ri-4!99r..=-?:== a_. :: v

19

3.23 Sallent Features of Maravakandy Resewoir Location Nilgiris N&restTown Udhagamandalam

River Avarahalla Stream

Purpose To provide subsidiary storage for Moyar Power House Catchment Area 2o.z@) AyY*, Years of Cons&uction 1947

Type Masonry Dam with earth bund Capacity 0.959 Mcum I L tez Height 2l.79m[-€ngth 83m .* ro.1 lz +,^,"(tl I Ui Siiltway '.i*+ Discharge Capacity :0.821 M cum Crest Length 45.72m Crest Level +914.4m Type ofGare Lift Type ,#y,ffi Size 12.192mx3.502m lx"'?rrt' \,e''^ t'' Reservoir : Gross Capacity za.az@ Ma,.^ 4T, Effective Capacity MWL FRL MDDL

Scour vent Size w ; ^9'n Y?h\" 20

3.2.4 Rrinftll @ na"fat is minimum around Ootacamund (1376.20 mm) in the eastemr part of the district. It gradually increases towards west and attains a maximum around Gudalur (2269.00 mm). The annual rainfall at Maravakandy site along with Annual average is fumished as shown in annexure.

mrh h*

I* ffi

l$'.e ttillbrr 21

Annual Rainfall (1965-2015)

25m

E 2000 E 15@ 10@ .g a oo-. aa a 5m G, 'aa 0 1960 1970 ud ;o Year vv .') ,p'"c orainral .Averaseno.,n"r() f-"{]r/ r\ \J [-t "'^

-r"- gpiL monthly rainfall data from 200.2 to 2015 is analysed in seasonwise pattern namely fiL.' non monsoon (Jan-May), south west monsoon (June-Sep) and north east monsbon (Oct- \"*t ' rD' .\, Dec). A trend analyses of rainfall data for periods (l 970-80), (l 98 I -90), ( I 99 I -2000)

and 2001-15 are plotted. Trend analyses was carried out and fuinisheaGi6ill frenO analyses clearly indicate decreasing rainfalt trend up to 2000 and increasirig from 2001 to 2015. e very trieh S.T9 rainfalt of [4r4#qs witnessed inpooe. 5,L) I hoq'4o I 3.2.5 Inflow and Outllow The monthly inflow in to the dam was analysed from the time of inception. The total capacity of the reservoir is 0.959 Mcum. Analyses of the inflow data from

201 I indicates that the reservoir has received sufficient inflows.

The inflow and outflow of Maravakandi reservoir have been collected for the ,AQperiod from 1965 to 2015 and the same are enclosed in this report in the form of statement as in Annexuri/The average annual inflow and outflow of the Maravakandi I reservoir is calculated.- P 22

CHAPTERry

4.0 Generel - Sedimentation studies

For conducting sedimentation survey of any reservoir, a water spread map prepared at the time of construction of the reservoir or at the time of completion ofthe same should be collected. This will forrn the basic map for the calculation of the sediment deposited over the years. After studying the plan, a reconnaissance survey along the full reservoir level should be made. The present bed level should be found out by conducting hydro graphic survey as well as ground suwey depending upon the water level in the reservoir. After finding out the present bed level of the reservoir, by computation the present capacity, and there by the reduction in capacity or the total quantity of silt deposited over years from the date of construction to the present day or from the previous sedimentation survey to the present day can be calculated.

4.1 Methodologr

The sedimentation studies involve the following: l. Preparation of base map (water spread map)

2. Reconnaissance survey.

3. Topographic survey.

4. Hydrographic survey to find out the present bed level.

5. Collection of soil samples and their analysis.

6. Preparation of contour map for the present survey.

7. Working out the present capacity ofthe reservoir and silt deposit rate.

8. Analysis of data and presentation ofresults. 23

4.2.0. Catchment Area map

The map was prepared from the Google Earth Map as there is no ftrtchment

The original water spread are{I map of Maravakandy reservoir was collected from Maravakandy dam section oflice ( TANGEDCO) and it was not to scale. As we

require precise scale for calculation purposejdthe new water spread area map was prepared from the Google earth map and it is copied into section sheet. From the section sheet, the East and North co-ordinates were taken along the periphery of FRL line. By adopting Software Auto Cadd 3D and applying X, Y & Z co-ordinates, the new water spread area map w.rs prepared. This map is used as the base map for this

survey for preparing contour map and worked out the capacity calculation.

4.2.2 Reconnaissance survey

Reconnaissance survey provides the data that enables to study the advantages

and disadvantages of a variety of routes and then to determine which routes are feasible. Begin with by studying all the existing maps that show the area to be surveyed and finding all the possibilities for executing the survey works like Topography and Hydrographic survey.

In reconnaissance survey, studyrng the existing maps is an important for the actual field work. Studlng these maps and aerial satellite photographs, if any exist, will often eliminate an unfavorable route from further consideration, thus saving the reconnaissance field party much time and effort. Contour maps give essential information about the life of an area. Aerial satellite photographs provide a quick means for preparing sketches. Direct aerial observation gives an overyiew of an area that speeds up later ground reconnaissance if the region has already been mapped. Begin the study of a map by marking the limits of the area to be specified terminals to be connected. Whether or not there are any existing routes, ridgelines, watercourses, mountain gaps, and similar control features, Study the terrain that will permit moderate grades of contour levels. Use a profile arrangement that makes it possible to fill depressions with the cut taken from nearby high places. Mark the 24 routes that seem to fit the needs and that should be reconnoitered in the field. From the map study, determine grades; estimate the amount of siltation and the present capacity of the reservoirs. 4.3 Topographic survey The datum in WGS 84 is used for the entire Survey. All levels refer to MSL. The survey was carried out to true north by applyng necessary correction in the total station. Leica total station was used for the transfer of Bench Mark marked in the Northern abutment of Maravakandy dam. This instrument was used for measuring the elevation and transfer of reference levels from the Bench Mark to other identified points. This instrument has the telescope length of 170 mm and a minimum focusing distance of 200 m. It has the leveling accuracy of + 1.0 mm for I km double run leveling. The land survey was carried out using the Leica Laser total station & It automatically calculates the horizontal distance, vertical distance and slopes in the internal memory. The stored data can be downloaded to computer using the interface.

Fig Theodolite details

Telescope Magnification 30x

Aperture 45 mm ( EDM : 48 mm) Resolving power

Display Resolution (selectable) H & V l" I 5",0.21 | mg, 0.005/0.02mi1 Accuracy (ISO 12857-2 1997) 2

Display LCD, 8 digits x 2lines w/backlight Display location On both faces 25

Compensator IDual-axis y"4 compensator, working range ,{'

Dust and water protection rP66 (rEC60s29) Weight with handle and battery a.7ke (10.31b.) Battery LRI4/C batteries x2

Continuous use with alkaline batteries Approx. 75 hours

Data storage 10000 points

Disp-tay resolution 0.001

4.4 Hydrographic survey to lind out the present bed level

The hydrographic survey (sedimentation survey) is to be carried out periodically for every reservoir. Conventional method, Remote sensing technique and DGPS based lntegrated Bathymetric Survey are used to determine the storage capacity of reservoirs. In the conventional method conventional equipment like theodolite, level, sextant, range finder, sounding rods, echo-sounders, current meter,

motor boat etc. are employed.

In continuation ofthis, lvl/s Ocean Engineering Consultancy Survey extends its services by providing suitable expertise Engineers, required technical assistants, operators, boat operators with assistants, computer system operators. The Capacity survey was commenced and carried out the bathymetry and topography survey using

IBS boat and its survey equipments provided by the Watershed Management Board - division, Pollachi,. dlring 22nd February, 2016 to 26th March, 2016 ; tn"!ffi"- rur G 'i h-.. .','. I t. ft zt.,-.1 'egien 'as shewn bel'ow. This report presents the results of the bathymetry & topography profile survey carried out in the MARAVAKANDY nA@in Nitslris District, in Tamilnadu. Bathymetry Soundings i profile survey is carried out using Eco sounder,.-= DGPS, Trimble. Total station and with its accessones. / " t' "'-'- 0!y\1 ^..),,- ,+ \ Y 26

4.5 Collection of SoiI Sample and their analysis

Hence, -R.!J_q9gg1-9.- JesSYsl!-ls in dead storage leveJ. eighteen number of soil samples were collected near the middle of water spread area ; )I of sieves. and boundary of FRL. The samples were analysed using the standard size (,1-i".d- ,. collectedar. **"dfl' r -1" [he map showing the location of the soil samples 'f curve, Grouping of soil sample and Soil -)1 of this report. The particle size distribution 5r*' statement showing a"' analysis chart are drawn and appended in Figu#respectively. A .^6\n^t'? [''' 't+<''.o+*'e I Q nA the percentage of particles size distribution is preparea'

4.6 Preparation of Contour maP

Hydrographic survey are The data collected within the water spread area by processed with Auto Cadd 3D for computed in the X, Y & Z co-ordinates and prepared at an interval of 1 meter preparation of contour map' The contour map was in 25 Metres in X and Y directions as shown elevation and at intervals of 25 Metres X Z values in the Auto Cadd 3D the contour Figure No.2. By inputting the X, Y and been arrived' map and capacity of each contour have

4.7 ComPutation of CaPacitY using Eco soundsr single beam The bathymetry survey w:ts conducted instrumentwithitsaccessories.)LY&Zco-ordinateswereobservedforeachpointof into the cadd format using the the survey location area' Then it was converted these p"'* u*: required interface softwares. once [T9 t]*',,*: fndividual :t

level on the dai of survey and also 3D modeling of the reservoir up to the stoifr Now above till the FTL as solid portions' p create a object below the lowest of the dam and 1. Fix the bed level of the 3D Land f solid for the surveYed area' land' for top the same bed level and area as the 3D 2. Now for the 3D Water maintains level of 3D water use MFL provided.

3. Now for both the 3D water and 3D Land, area and bottom level are maintained same.

4. Using Autocad we can find the volume of solid @

Fig Computation of volume 5. To find out the volume of water stored deduct the 3D water with 3D Land we will v have the volume of water stored. \- 6. Finally the volume of the individual contour level as per the drawing (say 1 m)

! interval were calculated in the same analysis as explained above. \- 4.8 Analysis of the Dats \- Sedimentation data of Maravakandy reservoir collected based on the \- observation made during sedimentation survey have been presented in the following \- pmagraphs. These data have been analysed for different aspects, like Sedimentation rate, Depth versus Capacity relationship, Trap efficiency and Life of reservoir.

!, 4.9 Sedimentation Rate

\- The sedimentation rate is given in terms of m.cum/sq.km of catchment area. \- The factors that influence the rate ofsilting are \- l) Capacity llnflow ratio \- 2) The content of sediment in the inflow.

\- The highest rate of silting would occur with small capacity-inflow ratio and \' high sediment content in the inflow. Reservoin with high capacity - inflow ratio and \, low sediment content will have the least rate of silting. Capacity - inflow ratio, \, capacrty - watershed ratio Maravakandy reservoir have been worked out and detailed \, below

\' I (a) Capacity/watershed Ratio in 1947 :0.959 /20.72 \. :0.046 Mcum/sq.km (b) capacitv/watershed Ratio in 2016 : : l.llirl'.1;3,, --

\' II (a) Capacity of the Reservoir in 1947 : 0.959 Mcum. \, (Original capacity) \, (b) Capacity of the Reservoir in 2016 : 0.835 Mcum. (As per second capacity suwey)

v Silt deposition during 2016 :o.rz@ N\u)n, 29

III Average annual silt load (for 69 years) :0.124t69 (1947 -2016) :0.00179 Mcum. lV Silt deposition in % :1293

V Average annual silting rate in % :0.19

VI Average annual silting rate/Sq.km.catchment : 0.19 120.72 :0.00917

4.9.1 Depth Vs Capacity Relationship

Depth Vs Capacity relationship graph drawn for the existing relationship during construction and for this first capacity survey w:rs drawn and appended with this report in Figure No.14 4.9,2Trap Efficiency

The Trap Efficiency of a reservoir is defined as the ratio of the quantity of deposited sediment to the total sediment inflow i.e. the percentage of incoming sediment trapped. The Trap Efficiency is a function of the ratio of capacity to inflow. In the absence of correct particulars about the inflow, the ratio of capacity to watershed area is made use of. The Trap Efficiency primarily depends on the sediment load characteristics and the detention time of the inflow, and the age of the Reservoir. The detention time depends upon

I ) The ratio between the storage capacity and inflow, 2) The shape ofthe reservoir basin and

3) The type ofoutlets and operation schedule.

The curve adopted by Brune(1953) was used and estjlqirted based on i capacity and annual inflow. The Capacity fnno* *^@)ased on the -:Annual lr"u analyses of capacity in lg47- & 2016. I ,o the curve it ryas assessed as l00%.Maravakandy ieservoir' has got a low capacity - watershed ratio F.,' sq.km for. 1947 and 0.040 Mcum/sq.km for 2016. According to B.N.Murthy, in geneial-rftp reservoir with capacity watershed ratio is 0.0476 - < I mcum/sq.km with trap 90% and-ihu.reservoir with capacity - watershed ratio is t doi+ziD."u"vsq.km with trap 60%9' and one\it[ O.002300 mcurr/qq.km will trap '--/ \.--.}---'- --., .,) b.,'-, ' {o V'*"\' .i ' )" r ., 'j ,7-'. 30 about 30%. In general the rap efficiency decreases with the decrease of the capacity ratio.

4.93 Life of Reservoir

Life of the reservoir is the period of its usefulness for the desigted purpose. It depends on the rate of sedimentation. Reservoir life can be described in Geomorphic tenns as a three stage process and related with the following.

Staeel. Continuous sediment trapping. Stase2.A mdn channel will be maintained by scour, sediment deposition continuous on flood plain areas on either side of the channel. Stage3.The key to achiev$f fuIl sediment balance is the discharge of the coarse materials. Sediment in{low and outflow in balance.

Most of the worlds reservoi ?Sirnou, sediment management are in stage l. Only at a few sites stage 2 & 3 are investigated and implemented with necessary structural and operational requirernents. For our practical reasons the Life ofthe reservoir is the period of its service for the designed purpose. When the reservoir reaches 30% of its original capacity, it is considered to be useless for the purpose for which it has been constructed and fails to serve the mankind.

To assess the Life ofthe Reservoir, several methods are adopted. In Japan one Dr.I{ACHIRO KIRA OF KHAGWA University has developed an equation taking into account inflow is as follows:

Vs :0.214(c/i) "'ou

100 100 r s ------Vs 0.214(cl1)4473

Ys :467(cli)oa73

Where Vs : Annual mean silt deposition rate in percent

c : original capacity of the reservoir t.@ b. a-^,'y{ --- ItI I fy m cr,lr'^

I : Annual mean inflow into the reservoir t"@

ys = Number of years during which the silt will fill up

the reservoir completely

Itlaravakandy Reservo-ir Original Cqacity c :0.959 lvlcu.m- Average annual inllow for 5l years is :20.,107 M.cu.m. I (1965 to 2016)

0.959 Therefore (dD = -----:0.0468 g.otrba tv 20.407 o,o^1 Vs =0.214(0.0468)a'473 =0.9l0Jperyear /

:46'7 1--_-10'0' t, : 109.73 years

T.V. TAYLOR of LINTVERSITY OF TEXAS, USA has sugg€sted the following procedure to find out the life ofreservoir. Vn l-. =VR'

Vn Ri v \, R :1Yn/Drh I Where R is the ratio of the reservoir caprcity at the end of the year to that ofthe prrevious year. L V original capaoity (1947) :0.959 M.cu.m-

Vn criracitv ater 67 years (2016) :0.835 M.qrm. 32 a7 N =51

:-10.835 /0.959;o'ot+s

:0.9980

Mean annual silting rate : (l - R) 100 percent per year

: (l -0.9980)100 :0.20%

100 100 Life ofreservoir : R 0.9980 : 100.20 Years (or) 100 years While comparing the above two results arrived from different formulae the earliest occurence year for the life of reservoir is I 14 years. Hence this value is adopted for the life ofthe reservoir.

Water Leve! Volume in 3D Water 3D Land Volume in S.No (Height in Million Volume Yolume cum u) cum

1 916.08 3159504.73 2324607.32 83497.41 0.835 2 91s.08 2981009.89 2323218.61 657791.28 0.658 3 914.08 2802506.04 2318826.10 1183679.94 o.444 4 913.08 2624002.72 2307103.51 316899.21 o.317 5 912.08 2445497.42 2259296.41 186201.0'l 0.186

6 911.08 2266994.21 2172348.'.t9 946,46.O2 0.095

7 910.08 2088484.32 2050368.11 38'.t16.21 0.038 I 909.08 1909987.116 18963't9.95 13667.51 0.014 I 908.08 178503.24 166227.97 '--- ., 12275.27 0.o't2

10 907.08 1731483.23 1730426.51 10ffi.72 0.001 lx*5 33

CIIAPIER- V

5.0 Conclusion

Based on the data collected and the sedimentation survey conducted in the year

2016, the following conclusions have been arrived at

Marzvakandy 1 . Name of the Reservoir - 2. Year of completion - t947 3. Original capacity in M.cum. - 0.959,/ / 4. Present capacity in M.cum. - 0.835 - 0.124 / 5. Capacity loss in M.cum. / 6. Capacity loss in % - r2.s3 / loss 0'00179 7 . Average Annual capacity .inr% \Mrr$'4 - 20'72 8. Watershed area in Sq.km. / - g. Life of Reservoir in Years - 101 10. Trap EfficiencY in % - 72% / ./ 11. Rate of sedimentation in percentage per annum - O'19 check dam The rate of silt deposit considerably reduces by providing necessary spread area. The along the stream formation of silt trap while entering into the water officials concern may be checked the above facts periodically'

would be However, the rate of silting and reduction in the capacity of reservoir and watershed correctly assessed only after conducting repetition of capacity surveys

studies.

& &vwppq t 11 C5S-:-'- Assistant Engileer, PwD, wRD, Assistant Executive Engineer, Watershed Management Board, PWD,WRD, Udhagamandalam Watershed Management Board, Udhagamandalam (.Sl,l,' r-9v\- Executive -Engineer, PWD, WRD' Superintending Engineer / Director, Watershed Management Board, PWD, WRD, Pollachi - @2003 Institute of Hydraulics and Hydrology, Poondi - 602 023 \,

:t4

REFERENCES

l. Suweying and trvelling (Vol II) - Iknetkar.T.P. 2. Engineering Hydrology - Varshney.R.S.

3. Report on First Capacity Survey of Thunacadavu Reservoir- I.H.H. Repofi No.22014

4. Technical r€port otr Life of Reservoir - CBIP Publication No.l9 (edition 1977)

5. Technical r€port on Sedimentation Strdies in Reservoirs - CBIP Publication No.20 (edition l98l)

!n'l \^sril{ h Qvr*{ XSru--L-j-,/ ? --?f,

v

c

I 35

SL.NO DETAILS PAGENO

I Reconnaissance survey in Maravakandy Dam 36

2 Hydrographic survey in Maravakandy Dam 37

3 Hydrographic survey in Maravakandy Dam 38

4 Executive Engineer inspection in Maravakandy Dam 39 36

RECONNAISSANCE SURVEY IN MARAVAKANDY DAM 37 38

HYDROGRAPHIC SURVEY IN MARAVAKANDY DAM

-lffi;,-..s6xr 39

EXECUTIVE ENGINEER INSPECTION IN MARAVAKANDY DAM v f,/ tr 1, t/ /t0 \., u$(r^Irf,BunEs v ly SLNO I}Ef,AII.s PAGENO ! Aon€xurc I ModlyRsidll Statcmetr 4t v L Amo

RAIN FALL STATEMENT OF MARAVAKANDY DAM (in mm) ANNEXURE 1

District Year Jan Feb Mar Apr May Jun Jul Aug sep Oct Nov Dec Total

OOTY 2002 0.0000 0.2000 23.4000 49.1000 108.2800 404.0000 192.9000 572.4000 102.3000 191.2000 25.4000 2.0000 1671.1800

2003 0.0000 2.2000 84.0000 41.8000 4.0000 206.8000 360.8000 247.4000 58.6000 180.2000 49.2000 10.0000 1239.0000

200,4 5.0000 0.0000 0.0000 68.7000 238.0000 553.9000 208.2000 s93.8000 117.9000 129.0000 62.0000 0.0000 1975.5(m

2ms 13.0000 0.0000 0.0000 69.9000 94.2000 278.8000 91S.0000 582.0000 245.2000 241.0000 83.0000 87.0000 26m.l(m

2006 0.0000 0.0000 17.0000 27.0000 282.0000 416.0000 526.0000 270.0000 249.0000 154.0000 181.0000 1.0000 213r.0000

2007 1.0000 2.0000 0.0000 17.0000 99.4000 509.0000 711.0000 539.0000 434.0000 171.0000 54.0000 46.0000 2693.4Ur0

2004 o.oooo 2s.8000 133.7000 19.1000 86.9000 436.3000 644.9000 515.5000 196.1000 329.9000 48.0000 48.0000 2'A4.2lXrO

2009 0.0000 0.0000 40.3000 23.3000 137.5000 213.1000 14M.9000 526.6000 581.3000 343.4000 233.5000 30.2000 35t4.1000

2010 0.0000 0.0000 5.7000 63.0000 88.0000 353.4000 817.3000 1062.7000 485.5000 256.7000 211.8000 30.9000 3385.0000

2011 2.3000 8.3000 8.5000 116.5000 42.s000 704.0000 636.6000 537.2000 408.7000 79.5000 94.4000 10.oooo 2644.6000

2012 1.5000 0.0000 o.0000 48.2000 67.i1000 181.2000 257.0000 471.6000 319.4000 121.0000 1S6.S000 10.0000 1633.to(x'

2013 0.0000 0,0000 40.0000 54.0000 133.6000 s59.5000 1024.0000 513.8000 278.8000 108.2000 28.5000 0.0000 2rrur.a00O

201a 0.0000 8.5000 12.5000 23.S000 81.0000 112.8000 846.2000 502.1000 346.2000 189.0000 28.5000 17.0000 2157.3flX'

2015 0.0000 0.0000 24.0000 135.5000 1S8.0000 535.6000 299.0000 269.5000 239.S000 105.0000 254.0000 22.5000 2042.6(xX'

4t 42

ANNEXURENo.2

MARAVAKANDY RESERVOIRT ANNUAL INFLOW STATEMENT

Inflow Inflow Year Year in M.cum in M.cum 1965 4.890 t994 17.080 1966 44.4W 1995 16.970 1967 12.470 1996 25.530 1968 17.350 1997 r9 410 1969 23.920 r 998 13 330 1974 29.010 1999 18 410 l97t 3t.390 2000 18 070 1972 36.680 2001 19.2s0 1973 19.430 2002 18.490 1974 18.850 2003 15.510 1975 38.400 2004 6.721 1976 3t.230 200s 4.983 1977 30.950 2006 7.949 1978 29.850 2007 1o.493 1979 35.180 2008 8.578 1980 28.400 2009 10.832 l98l 28.400 2010 9.99t 1982 42.900 20l l 14.214 t 983 19.550 2012 13.614 1984 13.030 2013 10.652 t 985 33.860 2014 6.571 1986 28.740 2015 I1.021 1987 26.000 Total to +o.1 1988 19.000 ArE -297.66s,20.407 1989 17 830 1990 14. 150 l99l 21 .670 1992 24.470 1993 2t tto (r\ 43 ANNEXURENo.3

MARAVAKANDY RESERVOIR

ANNUAL OUTFLOW STATEMENT

Outflow Outflow Year Year in M-cum in M.cum 1965 2840 1994 1.521 1966 2.601 1995 t.737 1967 4.405 1996 0.979 1968 1.948 1997 t.8s0 1969 t,566 t 998 I .381 1970 2.255 1999 1.929 t97l 2.478 2000 0.693 1972 3.082 2001 2.293 1973 3 393 2002 2140 1974 2 432 2003 2.475 t 975 2.476 2004 o 6-12 a\ t976 l.698 2005 0 498 1977 2.176 2006 0.795 1978 2.116 2007 1.049 1979 3.952 2008 0.858 1980 2.913 2009 1.083 l98l 1.622 2010 0.999 1982 2.025 2011 I 421 1983 2.142 2012 1.361 1984 t.735 2013 1.065 1985 2.727 2014 0.657 1986 1250 201s 1.102 1987 2.447 4 6<4 19. 9^d 1988 3 207 1989 1.990 A^'....a-s ----:--aL:- I990 t.992 1991 2.569 t992 1.828 1993 2.834 44

ANNEXURENo.4 PERCENTAGE OF PARTICLE SITF DISTRIBUTION IN TI{E SEDIMENT SAMPLES COLLECTED IN TT{E WATERSPREAD AREA OF MARAVAKANDYRESERVOIR Type of Soil in % Coarse cbo- -o Gravel Medium Fine Silt EE Sand Remarks (E5 r00 - Sand Sand below az 600-212 2mm 75 mic 63 mic 63 mic mic S1 220 47 84 43.00 2.tn s.00

S2 184 61 12 34.00 1.00 2.04

S3 2.92 56.32 34.92 2.08 3.',t6

S4 0.84 28.60 66.56 104 2.96

S5 204 2s.88 67.96 l.l6 2.96

S6 1.04 59.60 37.04 0.84 1.48

S7 1.68 60.40 35.92 0.84 1.16

s8 136 38.32 53.88 1.52 4.92

S9 2.12 39.76 55.24 1.28 2.20

sr0 6.68 45.28 M.12 096 2.96

2.26 46.30 47.25 1.27 2.92 --dJ "'/ t ,},, or-_( or) r-^ ,rrr -Y b"r "y i s LIST OF FIGURES

SLNO DETAILS PAGENO

Figure I Maravakandy Dam Index map 46

Figure 2 Maravakandy Dam countour map 47

Figure 3 Land use (1990) 48

Figure4 Land use (2010) 48

Figure 5 Temperature 49

Figure 6 Monthly Rainfall (2002-2015) 49

FigureT Soil Sample Particle Size Distribution Curve 50 Figure 8 S,nshine Hours 5l

Figure9 Annual Rainfall ( I 965-20 I 5) 5l

Figure l0 Rainfall (1970-1980) 52

Figurel I Rainfall (1981-1990) 52

Figue 12 Rainfall (1991-2000) 53

Figurel3 Rainfdl (2001-2015) 53

Figurel4 Stage vs capacity 54

Figurel5 Capacity- inflow Ratio 54

Figure l6 Trap Efficiency Cuwe 55 @y Gottachalk and Gunner M.Brune) ((

FIGURE.I 46 48

Maravakandy Dam

Fig 3 Land use (1990)

a ttr-a IrErL.- (l rFr.r lbta.r I a*.lla. t I'I..r*lfrt td a

Fig 4 Land use (2010)

I-duse tadoovs clasrificatioe (?OI0) Nilgni.tuict

r-t!d I r-b la r.r-lr ra- ra.t. lf brrll.l ll ot-td lf ,rrbE - r-r,rd -cb 8/. ts PE MG AE AEE EE 49

Maravakandy Dam

Fig 5 Temperature

Aor it y .1rl Jd Aug S.t

I ccnrhr* I , atlrr: i".eit

Fig 6 Rainfall

Saorrrtr

2sahn

2oorrr.r :od v !a S ts{rrtt ts: E

llxllrltl 'tod

so.rrrr

Ja'| F.t ll.r l/Ly .lr'r .}ll Ar!3 S.9 O.t ,{or. Dc.

I Average rainfrl Averuge r.irdays -

5x rs PE MG AE AEE EE

\1 ( (((( ( ( (( ( ( ( ( ( ( ( ( ( ( (((.((( ( ( ( (((('( f (

MARAVAKANDY DAM

SOILSAMPLE PARTICLE SIZE DISTRIBUTION CURVE Figure No 7

()1oo z t,ch tr o80fr (Jtl z Q60l.l & IEI lrl <40 ,t E= i) (J

Retained 63 mic 75 mic 212 mlc 600 mic 2.0 mm 4.75 mm 6.3 mm 20 mm 63 mm 100 mm GRAIN SIZE &.a< ,1 1. (t FIGURE. T k'-\ *-6 v \=- i 51 f- MaravakandyDam l, t, Fig8 SunshineHours ., \, \,

! lA! v 2 B ra. - w I Ot lv ,lh \,

ott h AF frt lrr A{ 8." Olt rbr Olc v D Harr fy v v Fig9 AnnualRainfall I Annual Rainfall (1965-2015) 25m (, a zm E E l!i{x) . : -!--.-,. --- .. = -. t ^-a aaa-! - - a )r a -' Erm oroe&ll5o E a a a t cc aa-a ato t/ 5m o

! rro t970 1!80 1990 20m 2010 Nm i lv YeaI *S-'I I a rainfall aAv€raae nornal /a) F"{ -1- IJ "^\er- l v -'" I til- N PE MG v {.,${/ AE AEE EE r,, t/ 52

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Rainfall 197O-8O 1sx, 1600 1{X) E rzoo li rmo !am O rainfall !6m LirEar (rainfall) 4{X) 2g) - o to to Er..rd

Fig ll Rainfall Rainfall 1981-90 1/{)0

12(X) E lmo €sm t rainfrll E.-a ts 4,q) oLirear (rainfall) 2@ - o

sy'rs PE MG {Yu*' AE AEE EE 53

Iv{aravakandy Dam Fig l2Rainfall

Rainfall 1991-2fiX1 1&X) 16m 1{X) E 12(X) € roo -fem i6@ 4m 2(D o

Fig 13 Rainfall

Rainfall 2001-2015

2500

2mo

E rr* ? E lmo t rainfall 'ca Lirrcar (rainfall) 5m -

0 P I\' N,\r1\rNirl\rN '\' @oN888 sOYcaFONSo!888FBBB

I€[ bY, Is PE MG \N \uv AE AEE EE KY 54

L Marzvakandy Dam

Fig 14 stage vs capacrty

Stage vs capacity 914 915 914 E e12 f, sro 9eG 96 9()4 9o2

""s{sc{"rdi"r*1""-{,--*}"{.-t'.""**""fVol (Mcum)

Fig 15 capacity- inflow Ratio

100 E T g 0o E E T B 8 T a fra{rahd raAtrrrt I 40 E Enib.CuEFor Ncrnrd hrtd hrGdrr t t lo a

E roo E Gap*lty: fmow Betle

Fig.l5 BRUNE'S curve of trap efficiency ofa reservoir

REF : Brune G. M, 1953. Trap Efficiency of Reservoirs. American Gmphysical Unioq 34(3), pp. 407419. S/.'Is PE MG AE AEE EE MARAVAKANDY DAM TRAP EFFICIENCY CURVE Figure No.l6 (By Gonachalk and Gunner M.Brune) Y

E (J

!t -^W'^ o. A

F ': 012z r 36 48 60 '12 t4 96 rr)E 120 R.es€rvoir Storage capacity in 1000 Cu.m. per sq.krn. drainage Capacity Watershed Area Year Capac ity,lvatershed Sediment Trapped in M-cu.m in Sq.k.m Ratio In PerceDlase 2016 0.E35 20.72 0.040299 460 ') ( Ua

(--

z7o Primffily highly flocculated and P \ 860 Coarsc grahad Scdimerrts 1..t M€dium C)rve Eio kirnarily Couoidal and Fl40 disFrsed a Finc graincd Sedimarts .E 30 .,20 l0 { !!E- 9l o oc, o o 9 E gE Y eoocio €Ei ii -id-oo Ratio ofcapaciry to Armual bflos Capacity Average annual Year ilflow Capacity/Annual Sediment trapped in in M.cu.m In M.cum. Inflow ratio Percent 20r6 0.835 20.40'7 0.M092 72.0 V ' -Y r* \ rt \a rs gy PE MG \.\''t rY AE AEE EE

I srrc/latt Co,EirE LrEjE \, 9 .I,t,rrr,'qlrcru'l Jl --"- It GovERNr,rENr oF rAl.rrLNAD u f;;*-----'-=' I \, wArER REsouRcEs oepliir.renr i-;------Ilff==-*t \, From -l^'-o"' Er.G.Ralendran, ll.E., The Chief Englo€€r, WRO, v Project Director & Design Rege6rch & Constructron Superintending Engineer(i/c), PwD, WRD, Support-(5RCS), State Proiect Management Unit, DRIP, Chep?uk, N0.6, Palar House, Kamarajar Salai, Chdnnai-s. v Chennai-0s. \. "' v insom u(oqmail, caio t Lr.r{o. F 1005/DRIP/sPMU/2014 Dt. 12.11.2015 t Sir, Sub: Dam Rehabilitation anct Improvement Project ( DRIP)- Conducting sedimentation study in 11 Tamil Nadu dams (8 wRD and 3IANGEDCO dams) during the year 2015-16 under DRIP at an estimated cost of Rs. 45.00 lakh-Approved by the w Empowered Committee - Administrative Sanction Accorded- J Government Order Communicated - Reg. Ref: G.O. {Ms) No.201 Public Works (WR 1) Department dated Y 05' 11'2015' * r:r,r + \, I herewith enclose the copy of the Government Order (G.O) cited \- for "Conducting sedimentation study in 11 Tamll Nadu Dams (8 wRD and 3 TANGEDCO dams) during the year 2Ot5'16 under \, DRIP" at an estimated cost of Rs. 45.00 lakh as approved by the Empowered Committee for information and necessary action. l- the cited ! Enclr Copy cf G.O. t ff.;,,-if 4,,,, eroiect Dlre'ctor, SPMU \, *..F11 Copy submitted to the Chief Engineer, !VRD, O&M, Chepauk, Chennai-5. v Copy to the Director, PWD. WRD, Institute of Hydraulics and Hvdrologv, v Poondi for information and necessary action. .dopy the Exe€utive Engineer, PWD, wRD, Watershed Management \i to Division, Pollachi for information and necessary action. t, v |, v fy t tfihGgpldcrctt/mef 4r,2fr 5f T.50.t.Hhtrrr!r0i.,."=f 1t1 I -d!df t wafl Fcli{ \, v 1v \,

... \, fy Abstract ! l:rrrbl,c ltorks oeparment - Wabr R€6ow€€6 D€pertmgnt - Dam Renab{rtatror r and .:r1t!'cvement Proreet (DRIP) - Propoid lor cordrcting S6d*lieEtat'on Study ,i t ' l.ir', 1 Nadu Dams durir€ the year 2015-16 under Dam Rehab{itatEn and irnorover."rErli i'i.4ec! al an eshnrate{ cost of Rs 45.(P lakh - Approved by tlte Enrpowered Cornrlltler.' - l:l ;.iJD: r,r. stratrve Sanction - accorded- Orders - lssu€d. v Public Wod(s llf,Rl) Dso.ltmcnt ii O-(Ms) No.201 t)*Ed:5.r1.20ts t- ldt!t', fl,-ntdi l9 S6*@!!rJi eioir.lrr 20 lr. ty

\, Read' .j1'rfds)No.34I Pubhc dorxs tt -qpt 1! Dsgartnent, dd 26 t1 2n10 G OtlidslNo.?80, Publrc Works {l.SF 1)Departrnonl. dsled 12.12 20r2 a (, LriMs) No.73, Pubric Wqks (l.Srt itD€pargn€nt, dabd ?3 5,?01 t j .! t, r,.ids) No 46. i,ubrrc vilo,l5 (l 5-B t, L;upadm€nt dated 25 2 ?0:a '12 v G O,l,r-s! No.253. Puirlie Wolks il .Spi 1i Oeparlmenl. dated 1E 2U1.1 Raad atsq a \, ,1 l-:or: the Chre, Engineer. Operatrcn and MainEnatce Weter Resou(ce,' f ;({.,rrlfirr.r)!. i-ette! No DS.S484i98 iEC 11.2015)-3. dated ?2 7 2t;1,. qdsL ln lhe Gove{rs'lent Ord€, firsl red aiove, tl|e GovBngnenl iave acco.tlec I ;drnrnistetive sar&n br the implom@dco of Dam RehrbiltEfion ard lmprovenr'rrt rfl Tamil ltad& rni8r lhe Wotld Bal* dsta.tca at s o, Re.745 43 Q6916 Out :ii ':'roiect cd fr fts.745 49 Crore3, an amount o, Ru.23.23 Croflrs has b€on albaed ior lnsttlultolral ! Strenrl6"n'nn co ponent under Dam Reha$ktio(l ard lmpdot 6ner{ Prqecl ? ln llre Governmenl Qrder secoRd read above. orders Hert issueo.lor ri= t- .cnslrlutrorr of Empotrr?red Committee under the Chairmanahip of Chref Secretary !c !.iivcrnmeoi lor sFtedy Efiplerncotsris.r €f Dem R€fiabine&on ar4 l|nFovemeat prcre.! \/ *irth World Bani loan asgtslance v 3 rn lhe Goyemmenl Order lhird read above, ihe Goverrulenl have accor(,i(, :(r,ilrriisiralive sanclion for r:onductrrg sedfEefltatlon sludy rn 10 Ulaier R{rsor.,r.-,,.. I .- 'r,]rrlment ! tams urlder Da,n Rehabilitathn and lmprovement ProJecl iiunn$ llre y,-'a! I l'j-;iO14 at an estlffated cost ol Rs.85.00 ld(hs Subsequently. in the G.)ye{omerrl Ord?r I '::r:r'lh rrlerl amendment have been issued to modfy 10 Water Resourr:s l)epart.neli \, \, I ti t, t tE rld{lodacgr rdir2frddJgElslzbstEH{fl'ffir 1n t {2fll?ot7 Pq?jps ty v

\, 2 \, rlam$ as I Water Resoures mparUnart (Karryappai piilur -th;'i;ru:rerrsri8nd 2 IANGEOCO Dams rGlennrrrrca,i \, end Damc)) and t"';da Darn by poqa;yar Dam iri ine Deparrmenr Dams Fti-*; ,p iii."c+r*"ra,on lv I[l$[ff",*.s study

4. ;- ltre Governmer rt Order ,fih r€acl above. .r.lmrnrstratrve lhe Governmeni have acc$,de.., sanclion for a sum of Rs 5g.00 v taf n iRupees Fifly Erghr , rkh ,,!,1.r l irv,/;1, jt! i:rlndrrc'ng Sedimenta*on Sludy ln g Water n"iorra", Department a:.ia ; T: riaar,,..,r .lams ,n Tamil Nadu durrnq the year ZOic-il 2 Nos of Ecfrr 1 No of Totat Statron aT:,l1rluT",I "nl-r-o-p"lnrn"ae srlinilp. an. ;i;l;il prov*ron for reparr*s ,i,,ri: t, l.r'r.loe:t i)(riiis and conlingencies th.. er under Dam Rehabr'iitarion anA r.proJere.i, p,;,*., ' 5 ihe chref Engrneer. operation & Ma,ntenarbe, l&arer Resources !i '' retter srxri' read abwe_ Llepadrnenr rrr reporred rhe propoarr for conductrng 'jluJy rn 11 Tamrl -has iedrrne or.rir:,r r : Nadu Dams dunng rhe'nar y"ii-z6ii rrnprovemenr prqect te under Dam Ret-abr,r1s1r.;,, ;.,. ar an estima& ro*t or ris L'ilpor.rered is m rskh waswqr apf,rovcdopr!,uveu (.,.. :,.. Conrmiltes vi& Agenda 6 on 13 07 201i. fequesre.r. .5 1u l"u fie Govemrnent to accsd d$inbhatrrae sanctlo.r conductrng sedinrentation study ixr in 11 ramir N"d;;ru durirlg the y6ar 2015-:6 \, and tmprove{renr urc,er _I,,L5"[:l:1:ft,on rro;ea at an estimeted ;;i;R;;,s6 ,",,n ,,

Sl.No Amounl irr Des6ription !akh a ! 1 .(Rs.l Sedimentation Study bi ii DamJ- v {8 WRD + 3 TAIJGEDCO Darns) fy Escatatron ol Rates ior ttre year :OiS f O@d:* :07 \. ! co-itir66'nEis 1 't2 45.00 ly

l, 7 l-he Government has examind th€ propmat of *€ ch,ief Engineer. r:rperalian \, Maintenance Waier Resources Departrneni-Ua*i and on the recornmendatron ct tti. l:'ttpo,r'ereJ i]afirnittee and hereby .i*ia lor","i#tive iakh (Rurleer senct,on for a sunr of RE 4i ;i:. \, Fortv five rakh onryj toward; . ;;;;;;g sedimentarion stuoy rn i I d i^.;atr:r Rr::\curces Deparrmenr b';; ir,,,,: ;rd tiA-tGeoco or*"y dunng the r,err l ,,: t, rndr.r [)arn Rehabilitation anO tmprovernent prof"ai-it" zt 5 Governrnent at$c crred :n,ri experjditure shouicj he resrricted to Iii actuel ii.rO iine'n"lance amounl should v or "out be rem, rd ;l[rti:,[o.ernnren*read ""*rni-inoi""]L;';ffi imrneciatervGrore--rr..,Jr-,u or ,,, I =

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