1.   Purpose and objectives

     This is a synthesis of conceptual and black box models based on absorbing the merits of both. It can be used for forecasting river flow and inflow to reservoirs.

2.   Description

     The SCLS model is in two parts. In the runoff formation part it estimates the total runoff from rainfall and evaporation considering the non-uniform distribution of soil moisture over the basin. A three-layer
model is used to estimate actual evaporation. In the runoff concentration part of model the total runoff is divided into various water sources. There are four types of conceptual submodels regarding the separation of the surface and subsurface runoff and ground water. "Switches" in the input file are used to operate different types of submodels:  PP1 one water source, PP2 two water sources, PP3 and PP4 three water sources. An optimizing technique is applied to optimize impulse responses for surface
runoff, subsurface runoff and ground water separately, and then to sum them at the outflow section.

     Recent SCLS models can solve rainfall-runoff problems with up to ten inflows from upstream. In the program an autoregressive procedure can be used to improve estimates and to update the results for real time forecasting.

     The SCLS model can be applied to calculate the hydrograph at the outflow section of any basin, for any period of years and time interval by changing the corresponding parameters.

3.   Input

     The time series of discharge or water level at upstream stations (if any) and outflow section, continuous rainfall records and average monthly evaporation records in the basin.

4.   Output

     Response function ordinates, volume for each water source, statistical characteristic values of observed and computed discharges and their comparisons.

5.   Operational requirements and restrictions

     The programme is written in FORTRAN.  It can be run on PDP-11 and VAX- 11 computers, and PCs (Windows environment) as well. Two weeks specialized training is needed for professional hydrologists to use this model.

6.   Form of presentation

     Program on floppy diskettes with user manual.

7.   Operational experience

     The model has been used successfully in humid and sub-humid region of China.

8.   Originator and technical support

     Water Resources Information Centre (Hydrology Bureau), Ministry of Water Resources, PRC, Beijing.

9.   Availability

     From the HOMS National Reference Centre for China.

10.  Conditions on use

     Cost of reproduction and mailing.