Estimate Design Flood Discharges For The Back Creek Streamgauge Site Assignment

Estimate Design Flood Discharges For The Back Creek Streamgauge Site Assignment Estimate Design Flood Discharges For The Back Creek Streamgauge Site â€" Assignment Example > AbstractThis paper describes the estimation of design flood discharge for the Back Creek stream gauge site known as BEECHMONT (DNRM). The design flood discharge has been estimated for the Back stream gauge site using the hydro meteorological approach. The paper also analyses the stream gauge frequencies and applies the empirical formula in drawing conclusions. The flood frequency analysis has been based on consideration of outputs of four techniques namely: Annual series, Partial series, the palmen and the week’s method and the new regional flood frequency estimation (RFFE) developed as part of AR and R update (Palmen, 2011). The work involved obtaining and reviewing stream flow data from Queensland DNRM water Monitoring portal (http: //water-monitoring. Information. qld. gov. au/), annual series FFA based on fitting a log person 3 (LP3) distribution to a yearly discharge maximum value, planning of the catchment area as well as the calculation of its area. Also, a compilation of estimates and selection of a set of design flood discharges and assessment of the rainfall frequency related to the January 2008 flood discharges event. IntroductionA flood in the context of this paper is considered to be an unusually high stage of a river. Floods are categorized into three broad categories: Minor floods, moderate floods, and major floods. Minor floods because some slight levels of erosion but normally no major damages are experienced. Moderate floods cause damages to the nearby properties though they are not very massive. Major floods are naturally serious as they cause a threat to human life and destroy properties in huge figures (Riggs, 1973). Floods occur in flood plains along rivers when water in the rivers fills up the stream hence bursting and spilling over to the nearest flood plains. Hydraulic structures are usually raised to prevent damages caused by floods. When laying these structures, due considerations need to be taken into account because these str uctures are susceptible to collapsing due to pressure mounted by the floods. If the hydraulic structures are poorly designed and implemented, more damages are caused to the surrounding environment and properties. Certainly, when floods are harnessed at location, it accumulates, and potential energy builds up in the form of pressure which can cause massive damages in case of collapsing. Due to the probable damages that can be caused by these hydraulic structures, estimates of extreme flood flow are very critical. Estimates of extreme flood flow are also used by engineers when choosing the quality of hydraulic structure to be constructed. The selection of the hydraulic structure will also be determined by the availability of resources such as finances. Design flood is defined as the flood adopted for the design of hydraulic structures. Design flood takes into consideration two types of data: the entire flood hydrograph or the peak discharge of the flood hydrograph. This work takes i nto account the latter case for simplicity. This work considers a Weir as the key hydraulics structure Analyzing flood recurrenceRecurrence interval can be defined as the average time length that separates two flood events. The reciprocal of flood recurrence is the probability that the flood will occur during a one year period. Stream gauges provide continuous records of discharge at fixed stations along a river. The largest event in a given year is called the annual peak discharge (Palmen, 2011). The analysis of flood recurrence used in this exercise has utilized a data set comprising of annual peak discharges for N consecutive years. The recurrence interval for each event in the data set has been being computed using the Weibull equation,