A practical approach to rainfall-runoff modelling in arid zone drainage basins

Abstract

A package of simulation models has been developed to study the hydrological processes controlling runoff and to predict flow hydrographs in the Indian arid zone. The models describe rainfall-runoff in the upland phase and the interaction between runoff and transmission losses in the channel phase, so as to derive the drainage basin outflow hydrograph. In the upland phase the rising limb of the hydrograph is predicted through a regression model and the recession through a conceptual analogue of discharge from a single leaky reservoir. The leaky reservoir is described by a continuity equation and by discharge-stage and storage-stage relationships at the outlet. In the channel phase the governing equations for movement of a flood wave subjected to the transmission losses are simplified through a time averaging process to develop an ordinary differential equation describing transmission losses as a function of distance, inflow, channel width, time parameters of flow and effective hydraulic conductivity. These models are simplified and developed to require a minimum of observed data for calibration. The package of models can be applied to ungauged drainage basins through parameterization.Une approche pratique de la modélisation pluie-débit dans des bassins versants de région aride Résumé Un progiciel de simulation destiné à étudier les processus commandant l'écoulement et à prédire les hydrogrammes dans les régions arides de l'Inde a été développé. Les modèles décrivent la transformation de la pluie en écoulement sur la partie amont du bassin et les relations entre l'écoulement et les pertes dans le réseau hydrographique afin d'en déduire l'hydrogramme à l'exutoire du bassin. A l'amont du bassin on prédit la partie ascendante de l'hydrogramme grâce à un modèle régressif et sa partie décroissante comme analogue à la vidange d'un réservoir unique. Le réservoir se vidangeant est décrit grâce à une équation de continuité et par une relation entre niveau de remplissage et débit de vidange à son exutoire. En ce qui concerne le réseau hydrographique, les équations gouvernant la propagation de l'onde de crue soumise à des pertes ont été simplifiées grâce à des moyennes prises au cours du temps en vue d'établir une équation différentielle ordinaire où les pertes sont fonction du débit entrant, de la distance parcourue, de la largeur du chenal, de l'évolution du débit et de la conductivité hydraulique efficace. Ces modèles ont été conçus sous une forme simple de telle sorte qu'ils n'exigent qu'un minimum de données pour être calés. Ce progiciel de simulation peut être utilisé sur des bassins non jaugés grâce à une paramétrisation.

A Parsimonious Hydrological Model for a Data Scarce Dryland Region

“…7). Significant transmission losses occur in overland flows during intense precipitation events, contributing to groundwater (Pilgrim et al 1988;Sharma and Murthy 1998) (see Eqs. 1 and 7 where flow from upstream areas appear as r ,t ).…”

Dynamic Hydrological Modeling in Drylands with TRMM Based Rainfall

“…In general form, the water balance equation at a point for time t can be written as: (1) where ∆SM is change in soil moisture storage, I is infiltration (vertical flow of rainfall into the root zone), ET is evapotranspiration (water loss from the soil profile), and GWR is groundwater recharge or drainage (vertical flow beyond the root zone layer). Currently, in DryMOD, leaf interception and water inputs from irrigation and runon contributions of water from runoff routing are not considered as vegetation cover is sparse in the pilot study regions considered here (Section 2.3) and a simplified water balance approach is found to represent well the key hydrological fluxes in drylands [15]. Rather than estimating effective runoff and soil moisture through horizontal runoff routing, DryMOD aims to (i) assess the sensitivity of the rainfall partitioning into runoff and infiltration to spatially and temporally distributed rainfall inputs, and (ii) calculate vertical fluxes (runoff and soil moisture) according to spatially heterogeneous soil properties.…”

Integration Techniques for Environmental Impact Assessment of Industrial Pollutants

“…Models dealing with the prediction or reconstruction of flood hydrographs are common, among them rainfall-runoff process simulation and flood routing [7][8][9][10][11][12][13][14][15][16][17]. In the field of rainfall-runoff modelling, the focus is often on flood hydrograph prediction.…”

“…A simple approach to rainfall-runoff modelling was proposed by Sherman [18] based on the unit hydrograph method, which hypothesizes that a watershed has a unique hydrological response function that is reflected by a unit hydrograph. Many researchers have described flood hydrographs and the recession limb as part of flood-routing procedures [16,[19][20][21][22][23]. In general, flood hydrograph analysis provides a simple method for estimating runoff volume in a watershed in response to storm patterns [24][25][26][27] or physical characteristics of the drainage area [10,11,15,28,29].…”