essibility M18 Hydrology The river's catchment in the town of Desing will be evaluated and conducted by a plethora of methods to identify flood levels from different return periods, so that

a possible design criterion can be the solution to provide safety of the region. As a result, four methods are implemented to find the index flood discharge QMED (median of flow) for a specified return period. These methods include: Annual Maxima using Weir formulae, FEH rainfall-runoff method, FEH WINFAP, and FEH ReFH. Three of the methods are derived from FEH which is known as the Flood Estimation Handbook is developed by the Institute of Hydrology in the UK, along with their established partners and organizations, is known to be the lead industry leader for calculating flood estimation and modelling softwares. Application of Weir Formulae for Annual Maxima Data of a 30-year annual maximum water levels was obtained from historic flood levels in the site from a period of 1978-2007. This approach is utilized to get QMED from the annual water level data using a formula for a broad-crested weir 5 m in width, 1 m in length, and situated upstream of Desing. The weir crest is 52.78 m AOD above a bed which is 52.00 m AOD. The table below demonstrates a relationship between the maximum heights and discharges each year: