Kodaiyar River Basin Introduction One of the oldest systems in Tamil Nadu is the “Kodaiyar system” providing irrigation facilities for two paddy crop seasons in Kanyakumari district. The Kodaiyar system comprises the integrated operation of commands of two major rivers namely Pazhayar and Paralayar along with Tambaraparani or Kuzhithuraiyur in which Kodaiyar is a major tributary. The whole system is called as Kodaiyar system. Planning, development and management of natural resources in this basin require time-effective and authentic data.The water demand for domestic, irrigation, industries, livestock, power generation and public purpose is governed by socio – economic and cultural factors such as present and future population size, income level, urbanization, markets, prices, cropping patterns etc. Water Resources Planning is people oriented and resources based. Data relating to geology, geomorphology, hydrogeology, hydrology, climatology, water quality, environment, socio – economic, agricultural, population, livestock, industries, etc. are collected for analysis. For the sake of consistency, other types of data should be treated in the same way. Socio – economic, agricultural and livestock statistics are collected and presented on the basis of administrative units located within this basin area. Location and extent of Kodaiyar Basin The Kodaiyar river basin forms the southernmost end of Indian peninsula. The basin covers an area of 1646.964 sq km. The flanks of the entire basin falls within the TamilnaduState boundary. Tamiraparani basin lies on the north and Kodaiyar basin on the east and Neyyar basin of Kerala State lies on the west. This is the only river basin which has its coastal border adjoining the Arabian sea, the Indian Ocean in the south and the Gulf of Mannar in the east. The basin is bifurcated into 6 sub basins on the basis of drainage pattern. The Kodaiyar river basin covers in the following Survey of India topo sheets:58H/2, 58H/3, 58H/4, 58H/6, 58H/7,58/H8, 58H/11 and 58H/12 of scale1:50,000 within the co-ordinatesLatitude: 08º 04’ 34” - 08º 34’ 35” and Longitude: 77º 05’ 53” - 77º 35” 39”. The entire basin falls in the territory of Kanyakumari district and a small portion falls in Radhapuram block of Tirunelveli district. The Kodaiyar river basin is spreading over 4 taluks in Kanyakumari district and part of one taluk of Tirunelveli district. Out of 10 blocks in this basin 6 full blocks comes under Kanyakumari District and one part block from Tirunelveli District are also included. Four Municipalities namely Kuzhithurai, Nagarcoil, Kolachal and Padmanabhapuram are located in this basin. Kanyakumari is the major tourist part of India which is famous for confluence of three seas of Indian Ocean, Arabian sea and Bay of Bengal. Vivekananda rock, Thiruvalluvar statue and Gandhimandabam are some of the important tourist places. Suchindram is famous for the holy place of Hindus and Padmanabhapuram is having the famous Palace of an ancient king. This basin are well connected with national highways, State highways and railway lines. The administrative setup of the Kodaiyar river basin is given in Table-1. Table-1: Administrative Setup Of Kodaiyar River Basin Block /Area Falling Withinthe Sl.No. District Taluk SubBasin Block Basin AreainSq Km 1 Kanyakumari Kalkulam Killiyur 10.399 Kalkulam Thiruvattar 0.887 Kalkulam Kuruthankode 91.277 Agastheeswaram Valliyar Rajakkamangalam 10.896 Thovalai 12.354 Thakkalai 99.713 TOTAL 225.526 Kalkulam Thiruvattar 85.670 Thovalai Perunchani Thovalai 69.128 TOTAL 154.798 Kalkulam Thiruvattar 111.762 Thovalai Thovalai 0.128 Pechiparai Vilavancode Melpuram 56.701 TOTAL 168.591 Kalkulam Killiyur 77.453 Kalkulam Thiruvattar 78.818 Kalkulam Kuruthankode 0.776 Kalkulam Thakkalai 32.047 Kuzhithuraiyar Vilavancode Munchirai 72.010 Vilavancode Melpuram 89.500 Thovalai Thovalai 0.737 TOTAL 351.341 Kalkulam Thiruvattar 47.317 Vilavancode Chittar Melpuram 125.689 TOTAL 173.006 Kalkulam Thiruvattar 19.753 Kalkulam Kuruthankode 19.977 Kalkulam Thakkalai 5.042 Thovalai Pazhayar Thovalai 248.968 Agastheeswaram Rajakkamangalam 133.541 Agastheeswaram Agastheeswaram 14.421 2 Tirunelveli Radhapuram Radhapuram 132.000 TOTAL 573.702 TOTAL AREA 1646.964 The administrative map of Kodaiyar river basin is shown in Fig. Fig. Administrative map of Kodaiyar river basin The river Tamiraparani (also called Kuzithuraiyar river) originates from the Western Ghats and flows towards the west in the Kanyakumari district and drains into the Arabian sea near Thengapattinam, The Kodaiyar river has three major tributaries namely Kodaiyar, Paralayar and Chittar. After the confluence of Kodaiyar with Paralayar, the river Kuzhithuraiar flows south towards the sea. Paralayar river has four tributaries namely Kalikesanar river, MasipatiAr, Chittar river and Pambar river which originates from the southern slope of Western Ghats at about 1500m above M.S.L.Perunchani Reservoir is located on the confluence point of tributaries across Paralayar.After the confluence of Kodaiyar and Paralayar the Mulliar joins Thamiraparani river near Thirukurichi village. The above tributaries join together and form a natural lake called “Perunchani Lake”. Ulakkaruvuar is also a tributary of Pazhayar river. Another tributary originates in the southern slope of Western Ghats from Nallakaimottai and Attumottai at an altitude of about 800m above M.S.L. near Black Rock estate and lower Victoria estate. Yet another tributary called Alathuraiyar originates in the southern slope of Western Ghats form Mahendragiri hills and finally joins Pazhayar river near Dharisanamcope. The Pazhayar finally enters the Arabian sea near Manakudy after traversing a distance of 35 km. Another tributary originating in the Western Ghats from Vallimalai and MaruvattarKundru at an altitude of about 900m above M.S.L. These tributaries join together at Karavilai village. One more tributary originates near Kotanallur area and joins Valliar river near Muttalakurunchi village. The Kodaiyar river basin in general is slopping towards southeastern direction with a rugged topographical relief and an undulating terrain.The Kodaiyar reservoir is located in between Virapuli reserved forest on the east at an elevation of 544m above M.S.L and Kalamalai reserved forest on the west at 529m above M.S.L. adjacent to Kodaiyar and Paralayar, there are two distinct and separate small basins namely Pazhayar and Valliar basins.On the eastern part of the basin the Mahendragiri reserved forest at an altitude 530m above M.S.L is located. Drainage The river Kodaiyar is the main river in this basin. The overall drainage of this basin is dendritic in nature. The Perunchani dam is constructed on Paralayar upstream and the Pechiparai reservoir situated on the northern territorial part of the basin. The Kodaiyar I and Kodaiyar II dam are situated west of Pechiparai reservoir. Kuttiar is another major tributary of Kodaiyar. The Chittar I and Chittar II lies west of the basin.Radhapuram canal runs south of Terkumalai (247m above M.S.L). Below Pechiparai reservoir, two main tributaries join the Kodaiyar river. One, called as Chittar I which originates at 500m above MSL in the reserved forest of western Ghats and join the Kodaiyar river on the leftern flanks. The other tributary, Chittar II originates at 600m above MSL. On contrast the upper catchment of Kodaiyar above Pechiparai (part of western Ghats) is covered with thick jungle. The river Valliyar runs south of Takkalai through Eraniel and down to Manavalakurichi. One of the tributaries of Pazhayar is called Thadaviar or Taruvannar river which originates in the south-western slope of Western Ghats from Karumpara near Mahendragiri estate at an altitude of about 1090m above M.S.L. and joins Pazhayar river at Viravanallu. The drainage map of Kodaiyarriver basin is shown in Fig. Fig. Drainage map of Kodaiyar river basin Geology For the geological study, the district resource map from Geological Survey of India is used.Major part of the Kodaiyar river basin area is underlain by gneissic terrain of hard crystalline rocks which includes Charnockites and Khondalites.Migmatite gneiss and Granites overlain the hard rocks and are identified as Warkalai sand stones which is equivalent to Cuddalore sandstone. Also, the sands of recent origin are noticed along the coast. Khondalite and Charnockite Groups of Archaean age occur in the western hilly area and in the plains migmatite-gneiss of Archaean age is found to occur. The coastal plain hosts rocks of Miocene, Quaternary and Recent ages. In the southern part of the basin along the west coast, placers deposits of heavy minerals (including illmanite, rutile, garnet and monazite) occur as localized pockets between Kolachel and Kanniyakumari. Beach Sands are exposed west of Kanyakumari, Rajakkamengalam, Manavalakurichi, Marthandam and Kuzithurai along the west coast in Kanyakumari district. Of these, the area near Manavalakurichi is well known for the occurrence of illmanite ores.Significant concentration of placer deposits occur between Vattakottai and Lipuram, the famous Manavalakurichi deposits, which extends over a length of 5 to 6 km. with a width of 3 to 5 m. The geology map of Kodaiyar basin is shown in Fig. Fig. Geology map of Kodaiyar river basin The geomorphological landforms identified in Kodaiyar river basinis shown in Fig. Fig. Geomorphology map of Kodaiyar river basin Land use The detailed landuse categories are given in Table-2. Table-2: Areal Extent of Various Landuse Categories Sl. No. Level I Level II Area in Sq.km. I Built Up Land Town & Villages 63.397 CropLand 163.201 Fallow land 101.755 II Agricultural Land Plantation 186.215 Total 451.171 Dense forest 79.636 Plantation 43.928 III Forest Reserved forest 653.193 Total 776.757 Beach sand 16.387 IV Waste land Land with Scrub 89.742 Scrub/Shrub land 107.273 Land without Scrub 65.671 Total 279.073 Reservoir 37.324 Tank 15.602 V Water Bodies River/Canal 19.95 Total 72.876 VI Others Salt pan 3.69 Grand Total 1646.964 In the command area the three main soils namely lateritic, red soil and brown soil are occur in the blocks of Thiruvattar, Munichirai, Kurunthencode, Rajakkamangalam, Killiyoor, Thuckalay and Melpuram.