GOVERNMENT OF TAJIIILNAD U PUBLIC WORI(S DEPARTMENT WATM. RESOU RCES ORGANISATIO N INSTITUTE OF HYDRAI'LICS AND HYDROLOGY POONDT 602023 i W[rr nsnEo MANAGEMENT BoA RD POLLACHI SEDIMENTATION STUDIES IN ALTYAR RESERVOIR FOURTH CAPACITYSURVHT I.H.H.REPORT No: 9 /2018 -: I l : GOVERNMENT OF TAMILNADU PUBLIC WORKS DEPARTMENT WATER RESOURCES ORGANISATION INSTITUTE OF HYDRAULICS AND HYDROTOGY POONDI 6020?3. WATERSHED MANAGEMENT BOARD POLLACHI SEDIMENTATION STUDIES IN ALTYAR RESERVOIR FOURTH CAPACITYSURVET I.H H.REPORT No: 9 / 2018 For official use only Poondi - 602023 2018 OFFICERS IN.CHARGE OF THE STUDY CHIEF ENGINEER, PWD, WRD DESIGN RESEARCH AND CONS'TRUCTION SUPPORT, CHENNAI Er.'R.VIIAYARAGHAVAN, M.E(Srnc.), F.t.E., F.t.V., SI.JPERINTENDING ENGINEER / DIRECTO& PWD, WRD INSTITUTE OF FIYDRAULICS & HYDROLOGY, FOONDI ET,KVENKATESWARALU A.M.I.E ET.V.SRIDHAMN, B.E., EXECUTIVE ENGINEER" PWD, WRD, WATERSHED MANAGEMENT BOARD DIVISION, POLLACHI ET.SPMBHAMf,AN, B.E, (i/c) ET.S.MALUKA, B.E, .J; ASSISTANT EXECUTTVE ENGINEER, PWD, WRD WATERSHED MANAGEMENT BOARD SUB DIVISION, POLLACHI Er.KARULMOZIII,B.E, 1 ASSISTANT ENGINEE& PWD, WRD WATERSHED MANAGEMENT BOARD SECTION, POLLACHI Er.G-ASHWINI, B.E., 1 \s CONDUCTING SEDIMENTATION STUDIES IN ALIYAR RESERVOIR IN COIMBATORE DISTRICT FOURTH APACITY SURVEY COI{TEITTS Chapter TitIE Page No Synopsis I 1.0 Sedimentation Studies 2 2.O Reservoir Sedimentation l0 3.0 Hydrology t4 3.1 Reservoir Details l4 3.2 Watershed Area r6 3.3 Climate l6 3.4 Rainfall l6 3.5 Analysis of Rainfall t7 3.6 Inflow and Outflow t7 4.0 Surveying l8 4.t Methodology 18 4.2 Preparation of Base Maps l8 4.3 Reconnaissance Survey l9 4.4 Topographical Survey l9 4.5 Hydrographic Survey 20 4.6 Analysis of Sediment Samples 2t 4.7 Preparation of Contour Map 2t 4.8 Computation of Capacity 2l 4.9 Analysis of Data 2L 4.9.r Sedimentation Rate 22 4.9.2 Elevation Vs Capacity Relationship 23 4.9.3 Classification of Reservoir 23 4.9.4 Trap Efficiency 23 4.9.5 Life of Reservoir 24 5.0 Results of the Study 26 6.0 List of Annexure 27 7.O List of Figures and Charts 28 8.0 List of Photographs 29 References 30 SYNOPSIS The Fourth capacity survey has been taken up by watershed Management Board Division under Dam Rehabilitation Improvement project (DRIp) in A]iyar Reservoir of coimbatore District, Tamil Nadu in the year of 2016-2o17.The object of this study is to assess the quantum of silt d.eposited, present capacity and useful life of the Reservoir. The resurt of this capacity survey is compared with that of the original data during the inception year 1962. This report'narrates briefly about the need of the study, methodology adopted besides the hydraulic features and rainfail in detail. preparation of the contour map and computation of the present capacity are clearry brought out in this report. The results are analyzed for the sedimentation rate, Depth versus capacity relationship, Trap Efficiency and usefur life of reservoir. The capacity of the reservoir as on 2017 is gl.zg74 M.cum as against the original capacity rr2.7s4 M.cum. Total quantity of sediment deposited in between 1962 and 2or7 (s6 years) is r4.9s66 M.cum. The average annual silting load is 0.2671 M.cum,/year. The average annual silting load per Sq.Km is 0.0014 M.cum/yearlSq.Km. As per analysis of Capacity Vs Watershed Area the trap efficiency of Aliyar Reservoir in the year 20r7 is 93%. The usefur life of reservoir is estimated as 301 years. SEDIMENTATION STUDIES 1.0 General The watershed Management Board Division was formed in 1973 vide G.o Ms pw No 857 Dept Dated 26 May 1973 to conduct sedimentation survey and watershed studies for the selected reservoirs / tanks in Tamilnadu. From b inception (1975), so far the sedimentation and watershed studies for the following reservoirs / tanks had been completed. I Phase (1975 to 1985) Estimate Rs.39.0O Lakhs - As per G.O.Ms.No.tZO4 pWD dated 26.11.1974 1. Emerald Avalanche (I Capacity survey - Nilgiris District) 2. Kundha Reservoir (I & II Capacity survey - Nilgiris District) 3. Pegumbahalla Reservoir (I & II Capacity survey - Nilgiris District) 4. Pillur Reservoir (I Capacity survey - Coimbatore District) 5. Upper Bhavani Reservoir (I Capacity survey - Nilgiris District) 6. Krishnagiri Reservoir (I,[ & III Capacity survey - Krishnagiri District) 7. Sathanur Reservoir (l & II Capacity survey - Thiruvannamalai District) 8. Vaigai Reservoir (I,[ & III Capacity survey - Theni District) 9. Aliyar Reservoir (I & II Capacity survey - Coimbatore District) 10. Mettur Reservoir (I & II Capacity survey - Salem District) 11. Manimuthar Reservoir (I Capacity survey - Tirunelveli District) I 2. Lower Bhavani Reservoir 0n & ry Capacity survey - Erode District) tr Phase (1985 to 1997) Esrirnate Rs.255.00 Lakhs - As per G.O.Ms.No.925 plfD dated 8.4.1986, Est.Rs.l26 lakhs & c.O.Ms.No.2s PW (Rl) dated 8.1.1999, Revised Est. Rs. 255 Lakhs 1. Amaravathy Reservoir (I & II Capacity survey - Coimbatore District) 2. Thirumoorthy Reservoir (I & U Capacity survey - Coimbatore District) 3. Willingdon Reservoir (l & II Capacity survey - Cuddalore District) 4. Berijam Iake (l Capacity survey - Dindigul District) 5. Barur Tank (I Capacity survey - Krishnagiri District) 6. Parson Valley Reservoir (I & II Capacity survey - Nilgiris District) 7. Ooty Lake (I Capacity survey - Nilgiris District) 8. Ponnaniar Reservoir (I & II Capacity survey - Trichy District) 9. Kaveripakkam Tank (I & II Capacity survey _ Vellore District) l0.porthimund Reservoir (I & II capacity survey - Nilgiris District) ll.uppar Reservoir 0 & II capacity survey - Erode District - currently Thiruppur Disrrict)) l2.pechiparai Reservoir (r & II Capacity survey - Kanyakumari Distric0 y l3.Manjalar Reservoir (l & II Capacity survey _ Theni District) l4.Mukurthy Reservoir (I Capacity survey _ Nilgiris District) lS.perunchani Reservoir (r capacity survey - Kanyakumari Dis'ict) lo.Veeranam tank (I Capacity survey _ Cuddalore District) 17. Wallajah Tank (I Capacity survey _ Cuddalore District) Itr Phase (1997 to 20Ol) Estirnate Rs.2S.00 Lakhs under WRCP (parr I) - As G.O.Ms.No.347 PW (Rt) Dept. dated 19.06.1997 l. Varathamanadi Reservoir (l Capacity survey - Dindigul District) 2. Glenmorgan Reservoir (l Capacity survey - Nilgiris District) 3. Maruthanadhi Reservoir (l Capacity survey - Theni District) 4. Chittar - I Reservoir (l Capacity survey - Kanyakumari District) 5. Perumal Tank (I Capacity survey - Cuddalore District) 6. Chittar - II Reservoir (I Capacity survey - Kanyakumari District) 7. Palar-Porandalar Reservoir(l Capacity survey - Dindigul District) 8. Pykara Reservoir (l Capacity survey - Nilgiris District) 9. Poondi Reseivoir (As per G.O.Ms.No.56 pW (Rl) Dept. dated 6.2.1998 for Rs.l.90 lakhs) (l Capacity survey - Thiruvallur District) IV Phase (2O01 to 2003) Estinrare Rs.18.00 Lakhs under WRCP (part II) - As per G.O.Ms.No.103 PW (R1) Dept. dated 1.3.2002 l. Kuthiraiyar Reservoir (l Capacity survey - Dindigul District) 2. Kamarajsagar Reservoir (I Capacity survey - Nilgiris District) 3. Parappalar Reservoir (l Capacity survey - Dindigul District) 4. Gadana Reservoir (I Capacity survey - Tirunelveli District) 5. Gomuki Reservoir (I Capacity survey - Cuddalore District) From the inception year of 1975 up to 1996, Central and State funds were provided for the above studies. For 3rd & 4th Phase during the year 1997 to 2003, the above studies for 14 reservoirs were conducted under Water Resources J project Consolidation (WRCP) aided by World Bank vide G.O. Ms. No.347 pW (Rl) Dept dated 19.06.1997 WRCP (parr-t). V Phase (2003 to 2OOZ) Estimate Rs.80.0O Lakhs (As per G.O.Ms.No.645 pW (R1) Dept. dated S.12.2003) l. Kadamba Tank (I Capacity & Watershed study- Tuticorin District) 2. Manimuthar Reservoir (III Capacity_ Tirunelveli District) 3. Maravakandi Reservoir (I capacity & watershed study- Nilgiris District) 4. Mukkurthi Reservoir 0I Capacity - Nilgiris District) 5. Maduranthagam Tank (I capacity & watershed study- chengalpet District) 6. Kodaganar Reservoir (I capacity & watershed study - Dindigul District) 7. Mettur Reservoir (III capacity by Conventional - salem District) 8. Aliyar Reservoir (III Capacity- Coimbatore District) 9. Amaravathi Reservoir (III Capacity- Coimbatore District) l0.Krishnagiri Reservoir (IV Capacity - Krishnagiri District) The above studies for all the Reservoirs/Tanks were completed. For Sathanur Reservoir - IBS survey completed upto +21 1.98M (FRL+222.20) VI Phase (2OO7 to 3O.O9.2O09) Estimate Rs.34.O0 Lakhs i 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 (Rl) Dept dated lt-07-2008 for ZOOZ-ZOO9. The proposal contains Sedimentation survey and Watershed Studies for selected five Reservoirs by conventional method and by Remote Sensing for Sathanur Reservoir. 1. Moyar Reservoir (instead of Pillur Reservoir) (I Capacity Survey - Nilsiris Distrid) 2. Thirumurthy Reservoir (III capacity Survey - Coimbatore District) 3. Manjalar Reservoir (lII Capacity Survey - Theni District) 4. Pechiparai Reservoir (III Capacity Survey - Kanyakumari District) 5. Veedur Reservoir (I Capacity Survey - Villupuram District) 6. Sathanur Reservoir (Remote sensing - III Capacity - Thiruvannamalai District) Due to non completion of sedimentation survey for the above reservoirs within the stipulated time that is 3l-03-2009, the Government approved the extension of time upro 30-09-2009 pw vide in c.o. (D) No.229 (Rl) Dept dated 22-06-2009. The above works had been completed on 30-09-2009 in arl respects, except sathanur Reservoir. VII Phase (From Ot.IO.2OO9 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.