Hydrology
How quickly catchments respond to rainfall, how rain becomes river flow and how floods and streamflow can be forecast more accurately.
What equations best estimate how quickly a catchment responds to rain in a given region?
To pick the best time-of-concentration equations for a region, we proposed correcting each equation to reduce its bias there. Reference values came from the NRCS velocity method in TR-55, and we tested the approach on 72 watersheds and subwatersheds in Khorasan Razavi province, Iran.
- Three equations performed best for these watersheds: California (correction factor 1.715), Kirpich (Tennessee, 1.721) and Arizona DOT (1.126).
Can real-time rainfall data and satellite images improve flood and streamflow forecasts?
We tested real-time updating of rainfall threshold curves on the Walnut Gulch watershed, using a rainfall-runoff model and a neural network. In a second study we built ANFIS and ANN models for long-term streamflow in the Talezang basin, Iran, using in-situ records, MODIS snow cover and a seasonal parameter.
- Updating raised the average hit rate by 28% and cut the false rate by 51%.
- Seasonal and satellite data had a great impact on accuracy, and ANFIS outperformed ANN.

