We can undertake several types of hydrological study including those assessing the flows in rivers and streams and studies estimating green-field runoff.
Flood Estimation Handbook (FEH)
For the hydrological assessment of flood flows in watercourses we would generally use the latest version of the Flood Estimation Handbook (FEH) software* which is the industry standard method for this type of work. Following the guidance set out in the Environment Agency's document, 'Flood Estimation Guidelines', this could include the use of the statistical or the ReFH rainfall-runoff methods as appropriate. The statistical method can produce estimates of the peak flood flow and in many ways is the preferred methodology for this. The ReFH method, on the other hand, can also produce peak flood flows but can in addition also generate design flood hydrographs.
Uses of FEH Study
An FEH study of the flow in a watercourse is often used in other engineering processes such as being a preliminary to the hydraulic modelling of a river or stream. This process, in turn, is often an element of a flood risk assessment.
The green-field run-off rate, (that is the estimated run-off rate from an undeveloped site), is an important consideration in the design of drainage systems for new developments. This is often used as the limiting flow from a completed site to ensure that there is no increase in the flood risk downstream.
For the estimation of green-field runoff we can utilise either FEH, IH124 or ADAS345 methods as appropriate.
The preparation of a hydrological study is site specific so please contact us for further information.
* Produced by the Centre for Ecology & Hydrology