Small and steep rivers respond very rapidly to rin and the crest stage is reached in a matter of a few hours. This poses the problem of indequate time for warning potential victims of an impending flood. It is therefore important to have a technique that give a reasonably reliably forecast within a short time, as any time gained in forecast preparation can be made available for warning and arelief purposes. To conform of this requirement the commmunitu Self-Help Method for flash flood corecast was developed. This flash flood forecast was developed. This flash flood model is able to give reasonably accurate forecast within a shor time and is adaptable to bsin changes. it is the aim of this thesis to apply the model on the Gombak River. The flash flood model requuires the preparation of a set of 6 flood warning tables from which forecasts are made. Each table is printed with probable crest stage values which depend on 4 variations, namely (i) the soil moisture deficit (ii) the total rain since the start of the storm (iii) the rainfall amount for the last time period (iv) the duration of the storm. The warning tables are prepared by means of a computer model. The warning tables for Gombak River have been obtained and teh checks made on them showed they are reasonably accurate.