Green Roof Curve Number Soil C

Impervious surfaces are assigned cn of 98.

Green roof curve number soil c.

T1 assessing curve number uncertainty for green roofs in a stochastic environment. No runoff from first storm when n 1 5. 5 42 since 2009 the number of different green roof systems on the market has expanded greatly. Amount and inter event dry period soil plant climate.

The curve number for infiltration trench is adapted to be 61 in accordance with the. 1 composite cns may be computed for other combinations of open space cover type. For a more detailed and complete description of land use curve numbers refer to chapter two 2 of the soil conservation service s technical release no. Latin hypercube sampling approach coupled with the antithetic variate technique is used to achieve efficient and accurate quantification of the uncertainty features of cn for a green roof system.

2 april 2010 prepared for the southern california stormwater monitoring coalition in cooperation with the state water resources control board by the low impact development center inc. Elements in green roofs subject to uncertainty considered are rainfall characteristics i e. Au tung y. N2 curve number cn is well known by hydrologists for estimating rainfall induced runoff from a catchment.

Effective cns for extensive green roofs roof thickness in. P q s q p actual retention potential retention actual runoff total rainfall where cn 25400 254 s. The curve number for green roofs for large rainfall events is given as 84 fassman beck et al 2015. 55 210 vi tr 55 second ed june 1986.

Despite substantial performance evidence in the literature the lack of a curve number cn or volumetric runoff coefficient c v to apply to prescribed methodologies for planning and regulatory submissions may be perceived as a barrier for implementation. 94 92 88 85 77 reprinted from the 2000 maryland stormwater design manual mde 2000 2009 chapter 5 p. Au huang w. The green roof used to establish the curve number was composed of a 3 deep soil 55 expanded slate 30 sand and 15 organic matter.

The soil had a total porosity of 50 6. Modeling of green roof as a shallow figure 3b. Au yoo chulsang. The site was in athens georgia annual rainfall of 48 5 inches.

The resulting curve number was 86 compared to 98 for an impervious roof. Curve number cn method is stating a following relationship between rainfall and runoff. Influence of growth media soil water retention 16 18 20 note. Paired rainfall runoff data were analyzed for up to 21 living roofs with varying.