A Physically-Based Approach for Evaluating the Hydraulic Invariance in Urban Transformations

A Physically-Based Approach for Evaluating the Hydraulic Invariance in Urban Transformations

Matteo Botticelli Roberto Guercio Roberto Magini Rosario Napoli 

D.I.C.E.A., Sapienza University of Rome, Italy

CREA-AA, Council for Agricultural Research and Economics

Page: 
536-546
|
DOI: 
https://doi.org/10.2495/SAFE-V8-N4-536-546
Received: 
N/A
|
Accepted: 
N/A
|
Published: 
30 September 2018
| Citation

OPEN ACCESS

Abstract: 

Transformation of urban areas satisfies hydraulic invariance (HI) if the maximum flow rate outgoing the area stays unchanged. The HI can be respected by dimensioning appropriate water storage volumes or low impact developments (LID) to balance the soil sealing and ground levelling effects. In order to comply with HI, some Italian regional legislation and river basin authority provide for the creation of storage tanks whose volume must be estimated through simple conceptual rainfall- runoff models. In this work a physically based approach for evaluating HI is proposed. It is based on interpolating the results from a large number of hydraulic simulations conducted using FullSWOF, which is an open source code developed by the University of Orléans. In this software the shallow water equations are solved using a finite volume scheme and friction laws and infiltration models are included. Simulations have been carried out  considering the effect of three properties of the area, that is: the saturated hydraulic conductivity of soil, the slope of ground surface and the standard deviation of ground elevation around the mean level. Using the results, interpolating laws for the peak discharge and the critical rainfall duration as function of the three basin parameters have been derived. A parametric hydrograph as a function of the basin parameters and rainfall duration is defined and a HI evaluation method  based on routing the parametric hydrograph is proposed. The results from this approach have been compared with those from non-physically based methods currently used, such as the direct  rainfall approach and the linear reservoir approach. The com- parison shows that the difference between these conceptual methods with that one proposed here is strongly dependent on the runoff coefficient value. It is also not possible to predict whether they are conservative or not.

Keywords: 

hydraulic invariance, land planning, soil properties, sustainable urban drainage systems, urban transformation

  References

[1] Pistocchi, A., La valutazione idrologica dei piani urbanistici – Un metodo semplificato per l’invarianza idraulica dei piani regolatori generali. Ingegneria Ambientale, XXX(7/8), pp. 407–413, 2001.

[2] Delestre, O., Darboux, F., James, F., Lucas, C., Laguerre, C. & Cordier, S., FullSWOF: A free software package for the simulation of shallow water flows. Mapmo, université d’Orléans; Institut National de la Recherche Agronomique, 2014, available at https://hal.archives-ouveres.fr/hal-00932234v2 (accessed 21 May 2015).

[3] Green, W.H. & Ampt, G.A., Studies on soil physics. Part I. – the flow of air and water through soils. The Journal of Agricultural Science, 4(1), pp. 1–24, 1911. https://doi.org/10.1017/s0021859600001441

[4] Mein, R.G. & Larson, C.L., Modeling infiltration during a steady rain. Water Resources Research, 9(2), pp. 384–394, 1973. https://doi.org/10.1029/wr009i002p00384

[5] Esteves, M., Faucher, X., Galle, S. & Vauclin, M., Overland flow and infiltration modelling for small plots during unsteady rain: numerical results versus observed values. Journal of Hydrology, 228(3–4), pp. 265–282, 2000.

https://doi.org/10.1016/s0022-1694(00)00155-4

[6] Hillel, D. & Gardner, W.R., Transient infiltration into crust-topped profiles. Soil Science, 109(2), pp. 69–76, 1970.

https://doi.org/10.1097/00010694-197002000-00001

[7] Delestre, O., Rain Water Overland Flow on Agricultural Fields Simulation, PhD thesis, University of Orléans, France, 2010.

[8] Audusse, E., Bouchut, F., Bristeau, M.-O., Klein, R. & Perthame, B., A fast and stable well-balanced scheme with hydrostatic reconstruction for shallow water flows. SIAM Journal on Scientific Computing, 25(6), pp. 2050–2065, 2004.

https://doi.org/10.1137/s1064827503431090

[9] Bouchut, F., Nonlinear Stability of Finite Volume Methods for Hyperbolic Conservation Laws, and Well-Balanced Schemes for Sources. Frontiers in Mathematics. Birkhäuser Basel, 2004.

[10] Rawls, W.J. & Brakensiek, D.L., Green-Ampt infiltration parameters from soil data. Journal of Hydraulic Engineering, 109(1), pp. 62–70, 1983. https://doi.org/10.1061/(asce)0733-9429(1983)109:1(62)

[11] Brevnova, E.V., Green-Ampt Infiltration Model Parameter Determination Using SCS Curve Number (CN) and Soil Texture Class, and Application to the SCS Runoff Model, degree thesis, West Virginia University, West Virginia, 2001.