Design of water reuse storage facilities in Sustainable Urban Drainage Systems from a volumetric water balance perspective.

This paper presents a methodology for designing water reuse storage facilities as part of Sustainable Urban Drainage Systems (SUDS) in urban catchments. The method analyzes the whole water balance of the catchment. The contributions to the balance are irrigation and precipitation; the outlets are evapotranspiration, seepage and discharge to the conventional sewage system. The internal system variations are the volume of water to be locally reutilized and the soil water content variation. A cost function that includes the costs of irrigation, discharge to the conventional sewer system and reuse of water locally is proposed to estimate the optimum volume of water to be reused. This approach for SUDS design goes beyond traditional events-based perspectives oriented to damage prevention. This method conceives stormwater as a resource and seeks its optimal use through the design of SUDS. Several types of urban catchments were studied, and the results show that the proposed methodology can be applied either for simulating SUDS behavior in urban catchments or for estimating the optimum volume of water to be locally reused.

Application of the system of environmental economic accounting for water SEEAW to the Spanish part of the Duero basin: Lessons learned.

The System of Environmental-Economic Accounting for Water (SEEA-W) consists of an agreed international framework for organizing hydrological and economic information in a coherent and consistent manner. The methodology yields to the SEEA-W physical tables focusing on the quantitative assessment of the stocks and their changes in a river basin during the accounting period. For that purpose, the information on the abstraction and water discharge is linked with the environment water stocks, which assesses how current levels of abstraction and discharge affect such water stocks. This study presents the methodology and results to fill out the SEEAW tables for asset accounts on the Spanish Duero basin. Duero is a transboundary river between Spain and Portugal where 80% of its basin area (78,860km(2)) runs into the Spanish territory. The Spanish part is divided in five zones and 13 management systems. The methodology applied the three models used by the Spanish Water Authorities for the planning and allocation of water resources in Spain: 'SIMPA' model (rainfall-runoff model), 'ASTER' model (hydro-meteorological model related to snow processes) and 'SIMGES' model (water management simulation model). The required information was collected with the support from the Duero River basin Authority and the Spanish Ministry of Agriculture. Special care was paid to issues such as: inter-annual variability, the selection of spatial and temporal scale, seasonality, disaggregation of human abstractions into use's type, and transboundary agreements. The results highlighted some drawbacks in the SEEAW methodology for the Duero basin. However, the developed balances are a valuable tool to support the decisions of the Spanish Duero basin Authority on the management and allocation of water in the basin and in the transboundary area with Portugal. Finally, the paper outlines some recommendations for future work.