Hydrological and Nutrient Budget Modelling of Surface Water of the Achankovil River, Western Ghats, India
An attempt has been made to develop a hydrologic and nutrient budget for Achankovil river watershed(area 1484 km2) in Western Ghats of India. The work was carried out in the year 2002 during three seasons i.e. premonsoon (February), monsoon (June/July) and post-monsoon (October). The water budget was determined using
the formulae dm/dt = S input S outputs + S (sources sinks). The inflow (precipitation, tributary and Achankovil river baseflow) and out-flow (evapo-transpiration and discharge from tributaries and Achankovil river) segments were measured following the standard procedure for three seasons. The result indicates that significant amount of water leaving (60.35 × 108 m3) the watershed to the adjoining Vembanad lake and ultimately into the ocean, which exceeds the water, entering (54.83 × 108 m3) the basin. The outgoing water (@ 9%) surplus may be due to overestimation of transpiration and the lack of estimation of the water input from the intermittent streams in the present study.Nitrogen and phosphorus balances are also calculated by LOICZCABARET budget model. 20,976.86 × 106 m mol/yr and 19,655.1 × 106 m mol/yr of nitrogen and phosphorus were lost or utilized within the Achankovil river basin during the study period. More detailed study on short term and variation will certainly help us in dealing with the various sources and the contribution by main stream as well as intermittent streams.
APHA, AWWA and WPCF (1995). Standard methods for the Washington DC.
Bala Krishna Prasad, M. and AL. Ramanathan (2005). Solute acquisition sources and processes in the Achankovil River Basin, Western Ghats, South India. Hydrological Sciences Journal, 50(2). In the press.
Black, P.E. (1996). Watershed Hydrology, 2nd edn. Ann. Arbor. Press Inc, Chelsea, Michigan.
Brooks, K.N., Folliott, P.F., Gregersen, H.M. and L.F. DeBano(1997). Hydrology and Catchment of Watersheds, 2nd edn. Iowa State University Press, Ames, Iowa.
Campbell, I.C. (1978). Input and output of water and phosphorus from four Victorian catchments. Australian J. Marine and Fresh Water Res., 29: 57-58.
Dawdy, D.R. and W.B. Landbein (1960). Mapping mean aerial precipitation. Bull. Int. Assoc. Sci. Hydrol., 19(16): 1-30.
Denmend, O.T. (1990). An ammonia budget of Australia. Australian J. Res., 28: 887-900.
Gordon, G.D., Boudreau, P.R., Mann, K.H., Ong, J.E., Silvert, W.L., Smith, S.V., Wattayakon, W., Wulff, F. and T. Yanagi(1996). LOICZ biogeochemical modeling guidelines, LOICZ Reports & Studies 5, p. 96.
Groisman, P.Y. and D.R. Legates (1994). The accuracy of United States precipitation data. Bull. Am. Meteorol. Soc.,75(3): 215-217.
Kohn, R.A., Dou, Z., Ferguson J.D. and R.C. Boston (1997). A sensitivity analysis of nitrogen losses from dairy farms.J.Mang., 50: 417-428.
Luo, W. and J. Goudriaan (2000). Dew formation on the rice under varying durations of nocturnal radiative loss. Agric. For Meteorol., 104: 303-313.
Martin, J.L. and S. Mc Cutcheon (1992). Hydrodynamics and Transport for Water Quality Modeling. Lewis Publishers.
McKee, L.J. and B.Y. Eyre (2000). Nitrogen and phosphorus budgets for the sub-tropical Richmond River catchment, Australia. Biogeochemistry, 50: 207-239.
Meybeck, M. (1998). Global Weathering from Surfacial Rocks estimated from River Dissolved Loads. Amer. J. Sci., 287: 401-428.
Moldan, B. and J. Cerny (1994). Biogeochemistry of Small Catchments. Wiley, New York.
Tavener, B. and M. Iqbal (2003). The development of a hydrologic budget to determine the nitrogen and phosphorus loads of the Ceder River watershed in Iowa. Environmental Geology, 43: 400-407.
Thiessen, A.H. (1911). Precipitation for large areas. Mon. Weather Rev., 39: 1082-1084.
Thornwaite, C.W. and J.R. Mathur (1957). Instructions and tables for computing potential evapotranspiration and the water balance. Publ. Climatol., 3: 181.