No abstract

Adaptation of stilling basins to higher discharges than those considered for their design implies deep knowledge of the flow developed in these structures. To this end, the hydraulic jump occurring in a typified United States Bureau of Reclamation Type II (USBR II) stilling basin was analyzed using a numerical and experimental modeling approach. A reduced-scale physical model to conduct an experimental campaign was built and a numerical computational fluid dynamics (CFD) model was prepared to carry out the corresponding simulations. Both models were able to successfully reproduce the case study in terms of hydraulic jump shape, velocity profiles, and pressure distributions. The analysis revealed not only similarities to the flow in classical hydraulic jumps but also the influence of the energy dissipation devices existing in the stilling basin, all in good agreement with bibliographical information, despite some slight differences. Furthermore, the void fraction distribution was analyzed, showing satisfactory performance of the physical model, although the numerical approach presented some limitations to adequately represent the flow aeration mechanisms, which are discussed herein. Overall, the presented modeling approach can be considered as a useful tool to address the analysis of free surface flows occurring in stilling basins.

Sustainable drainage systems are an alternative and holistic approach to conventional urban stormwater management that use and enhance natural processes to mimic pre-development hydrology, adding a number of wellrecognized, although not so often quantified benefits. However, transitions towards regenerative urban built environments that widely incorporate sustainable drainage systems are "per se" innovative journeys that encounter barriers which include the limited evidence on the performance of these systems which, in many countries, are still unknown to professionals and decision makers. A further important barrier is the frequently poor interaction among stakeholders; key items such as sustainable drainage systems provide collective benefits which also demand collective efforts. With the aim of overcoming such innovation-driven barriers, six showcase projects (including rain gardens acting as infiltration basins, swales and a green roof) to demonstrate the feasibility and suitability of sustainable drainage systems were developed and/or retrofitted in two cities of the Valencian region of Spain as a part of an European project, and

This paper presents the performance of a number of sustainable drainage systems (SuDS) in the city of Xàtiva in the Valencia Region of Spain relatively soon after their construction. The systems studied comprise two roadside swales, one detention basin receiving runoff from one of the swales and one green roof to a school. The SuDS were installed under an EU LIFE+ project intended to demonstrate their practicability, application and behaviour under Mediterranean rainfall conditions. Most of the systems installed were in new developments but the green roof was retrofitted to a school within Xàtiva which is a dense urban area. Full flow monitoring was undertaken and spot samples were taken to give a preliminary assessment of water quality performance. The early results presented in the paper demonstrate the effectiveness of the systems under typical Mediterranean conditions which comprise intense rainfall from September to December and little or no precipitation at other times of the year. It is concluded that SuDS can be effectively introduced in the Mediterranean region of Spain.

Biotic and abiotic interactions between the riparian zone and the river determine relevant hydrological processes and exert control over riparian and bordering upland vegetation types. Vegetation growth and development are mainly controlled by water availability on semi-arid regions so the closeness to the river yields a moisture gradient which clearly determines the boundaries between exuberant riparian zone and semi-arid upland. A mathematical model named RibAV is presented. Its conceptualization is based on the main worldwide ecosystem modelling approaches and field expertise. The implementation of RibAV that is proposed in this paper allows the simulation of the vegetation functional types distribution in riparian zones. An evapotranspiration index (E idx ) obtained through RibAV is used as criterion for long-term plant absence/presence prediction. Two permanent river reaches of semi-arid Mediterranean basins, the Terde reach (Mijares River, Spain) and the Lorcha reach (Serpis River, Spain), have been selected as case studies for the evaluation of the model performance. Several criteria based on the confusion matrix were used to analyze the efficiency of RibAV on the prediction of plant distribution. The model outstanding performance to establish riparian vegetation types distribution and the limit between this zone and the bordering upland is demonstrated in this paper; the strength of the E idx to classify plant functional types in riparian semi-arid environments is additionally proved. This is a pre-copyedited, author-produced PDF version following peer review of the article: García-Arias A., Francés F., Morales-de la Cruz M., Real J., Vallés-Morán F., Martínez-Capel F., Garófano-Gómez V. 2014. Riparian evapotranspiration modelling: model description and implementation for predicting vegetation spatial distribution in semi-arid environments. Ecohydrology, 7: 659-677.