Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Development and application of wapros model for hydrologic simulation in a watershed

Auteur : Ranjit Kumar M,

Université de soutenance : Anna University

Grade : Doctor of Philosophy (PhD) 2016

Résumé partiel
The currently available hydrologic models, mostly developed in the USA, Europe and Australia, require more input data than are generally available in India. Many hydrologic models simulate daily flows, which when applied to small and medium sized watersheds, mask the peaks and troughs and produce only averaged flows. These situations necessitated the development of a new simulation model suitable for medium sized watersheds and limited data available in Indian conditions, and hence this study. The unified framework, dovetailing water balance equation (WBE) into the hydrologic simulation, was used to develop the new model, titled as WAtershed PROcesses Simulation (WAPROS) model. It is a deterministic, lumped, continuous, predictive, conceptual and hourly watershed model.
The following mathematical relationships were newly developed for incorporation in the model : i. estimation of areal average values for rainfall and hydraulic conductivity, when spatial variability followed lognormal distribution ; ii. disaggregation of daily PET into hourly potential evaporation and potential transpiration ; iii. overland flow modelling, obviating the need for pre-fixed unit hydrograph ; iv. baseflow modelling, using linear system approach ; v. macro pore flow modelling, using fractal dimensions ; and vi. new error and evaluation criteria.

The model simulated hydrologic processes continuously with the limited inputs commonly available under Indian conditions. A model closure procedure was developed and incorporated in WAPROS model, to accomplish closure of all hydrologic storages, with closure errors of respective storages.
The model simulated the hydrologic storage positions and process values on hourly basis, and accumulated the hourly data into daily data, which would be useful in watersheds where only data on hourly rainfall and daily channel flow were available. For water balance analysis, storage based WBE, process based WBE, independent closures of all storages, and water balance ratios were generated within the model. The model also estimated the storage closure errors, model error and the simulation error, the values of which reinforced the new concept of hierarchy of errors in simulation modelling.
WAPROS model simulated 15 hydrologic processes namely interception, evapotranspiration, soil detention, surface detention, structural detention, infiltration, percolation (UL and LL), macropore flow, variable source area flow, interflow (UL and LL), overland flow, baseflow and channel flow, interacting with 10 hydrologic storages, on hourly basis. The hydrologic processes have been differentiated into additive and depletive processes based on its action on the storage ; and lumped and elemental processes based on their constituent relationship.

Présentation et version intégrale (Shodhganga)