Study On Theory And Technology Of The Rainwater Detention Tanks

Detention tank that is regarded as measures to control urban flood and non-pointsource pollution is widely used at home and abroad. Practice has proved that the detentiontank has a significant social, environmental and economic benefit which is the effectivecombination of the three. The papers study the storage of the detention tank, detentiontank influencing factors, detention tank comparison with other measures in economy.This article discusses the working principle of the detention tank, detention tankvolume calculation formula by the contrast at home and abroad. The paper discusses thepeak flow detention tank and non-point source pollution control detention tank volumecalculation process in SWMM. The detention tank volume calculation for rainwaterutilization, the paper focuses on the recommended simple algorithm and computercalculated process steps.The capacity of the storage tank size and set the location parameters and rainfallconditions, watershed conditions and pipe network are closely related. The paperdiscusses3kinds of external factors for the storage tank design parameters in theory andquantity. Rainfall conditions in the precipitation type and return period of the greatestimpact on the storage tank. The ratio of impervious catchment and the permeable area forthe pipe network and storage tank has a significant impaction.Pipe network parameters such as diameter and slope parameters which have fairimpaction need analyzing the impact of its role with combination of the two factors.After three kinds of external influenced factors discussed, this paper study thealgorithm of particle removal rate referenced to the ideal advection sedimentation tanksassumptions. The pilot model is recommended to validate and improve it.After the paper discussed of the factors influenced detention tank in theory andquality, according to the engineering example, the instance parameters of the project hadinput SWMM model. The paper use orthogonal experiment method to arrange the6factors include rainfall return period P, Chicago rainfall pattern the moderate peakposition r, the catchment area of permeable and impermeable area ratio, pipe networkchanges in the diameter, the slope of the pipeline and storage tank in different locationswith25trials, which factor has5levels where each factor is uniformly distributed in the25tests, the computer simulation results analyzed suggest that the two largest factors isthe return period and ratio of catchment permeable/impermeable area and the location of the detention tank followed by. In this example, the overflow points of the pipe networkdistributed in the upstream and downstream, otherwise, that the best results the detentiontank set position is the joint that is between the upstream and downstream seriousoverflow joints.In the same instance where return period equal s5, the catchment water permeabilityratio of40%, taking benefit/cost as principle the paper argue4technical solutions whichhave the same extent to mitigate flood flows and compare investment cost, we found thatthe project that detention tank constructed in both upstream and downstream economy isslightly better than the zoom mains slope program. It proves that detention tank to beeconomically viable only accounted for control peak storage.