Description: Combined sewer systems are designed to transport stormwater surface run off in addition to the dry weather flows up to defined limits. In most European countries, hydraulic loads greater than the design flow are discharged directly into receiving water bodies, with minimal treatment (screening, sedimentation), or with no treatment at all. One feasible solution to prevent receiving waters from strong negative impacts seems to be the application of vertical flow constructed wetlands. In Germany, first attempts to use this ecological technology were recognized in early 1990s. Since then, further development continued until a high level of treatment performance was reached. During recent years the national “state-of-the-art” (defined in 2005) was adapted in other European countries, including France and Italy. Against the background of differing national requirements in combined sewer system design, substantial developmental steps were taken. The use of coarser filter media in combination with alternating loadings of separated filter beds allows direct feedings with untreated combined runoff. Permanent water storage in deep layers of the wetland improves the system’s robustness against extended dry periods, but contains operational risks. Besides similar functions (but different designs and layouts), correct dimensioning of all approaches suffers from uncertainties in long-term rainfall predictions as well as inside sewer system simulation tools.

Description: The excessive use of water is damaging European groundwater and rivers: their environmental conditions are often below the “good status” that—according to Water Framework Directive 2000/60—should be reached by 2015. The already critical situation is tending to get worse because of climate change. Even in water rich countries, urban wastewater is still one of the main sources of water pollution. Currently, urban soil sealing and “conventional” rainwater management, which were planned to quickly move rainwater away from roofs and streets, are increasing the flood risk. “Green” technologies and approaches would permit a reduction in water abstraction and wastewater production while improving urban hydrological response to heavy rains. The Life+ WATACLIC project has been implemented to promote such sustainable technologies and approaches in Italy, however the results show huge difficulties: apparently water saving and sustainable urban water management have only low interest amongst the general public and even with public administrations and the relevant industrial sectors. In such a cultural and technical context, the project is bringing a new point of view to public debate. In the long term, the project will certainly have a positive impact, but most likely it will require more time than initially expected.

Description: Use and retention of river water in African highlands deprive communities in arid lowlands of their benefits. This paper reviews information on water use in the Ewaso Ng’iro catchment, Kenya, to evaluate the effects of upstream abstraction on the Lorian Swamp, a wetland used by pastoralists downstream. We first assess the abstractions and demands for water upstream and the river water supplies at the upper and the lower end of the Lorian Swamp. Further analysis of 12 years of monthly SPOT-VEGETATION satellite imagery reveals higher NDVI (Normalized Differential Vegetation Index) values in the swamp than nearby rainfed areas, with the difference in NDVI between the two positively related to river water discharged into the swamp. The paper next reviews the benefits derived from water entering the swamp and the vulnerability to abstractions for three categories of water: (i) the surface water used for drinking and sanitation; (ii) the surface water that supports forage production; and (iii) the water that recharges the Merti Aquifer. Our results suggest that benefits from surface water for domestic use and forage production are vulnerable to abstractions upstream whereas the benefits from the aquifer, with significant fossil water, are likely to be affected in the long run, but not the short term.

Description: This study examined the effectiveness of open-joint inter-locking pavers in a permeable pavement in cold (winter) conditions. A field-scale inter-locking paver cell (UNI Eco-Optiloc®) was built to evaluate the hydraulic performance and water quality improvements experienced during freeze-thaw and frozen conditions in Calgary, Alberta, Canada. Hydraulic performance was assessed using stormwater runoff reduction (peaks and volumes) and surface infiltration capacity. Water quality performance for removal of total suspended solids (TSS), total nitrogen (TN), total phosphorous (TP) and three heavy metals: copper, lead and zinc, was assessed. Results from the study demonstrated that the inter-locking pavers were effective in attenuating stormwater runoff peak volumes. The surface infiltration capacity decreased significantly due to the deposition of sanding and de-icing materials on the pavement surface during winter operation. Infiltrated stormwater was stored and treated within the pavement structure, which showed removal rates of 91% for TSS, 78% for TP, 6% for TN, 68% for zinc, 69% for copper and 55% for lead.

Description: Hydraulic fracturing is an industrial process used to extract fossil fuel reserves that lie deep underground. With the introduction of horizontal drilling, new commercial sources of energy have become available. Wells are drilled and injected with large quantities of water mixed with specially selected chemicals at high pressures that allow petroleum reserves to flow to the surface. While the increased economic activities and the outputs of domestic energy are welcomed, there is growing concern over negative environmental impacts from horizontal drilling in shale formations. The potential for water contamination, land destruction, air pollution, and geologic disruption has raised concerns about the merits of production activities used during extraction. This paper looks at the impacts of horizontal drilling using hydraulic fracturing on water supplies and takes a comprehensive look at legislative and regulatory approaches to mitigate environmental risks in the Marcellus shale region. The overview identifies shortcomings associated with regulatory controls by local and state governments and offers two policy suggestions to better protect waters of the region.

Description: Many agriculture-based economies are increasingly under stress from climate change and socio-economic pressures. The excessive exploitation of natural resources still represents the standard procedure to achieve socio-economic development. In the area of the Moulouya river basin, Morocco, natural water availability represents a key resource for all economic activities. Agriculture represents the most important sector, and frequently occurring water deficits are aggravated by climate change. On the basis of historical trends taken from CRU TS 2.1, this paper analyses the impact of climate change on the per capita water availability under inclusion of population trends. The Climatic Water Balance (CWB) shows a significant decrease for the winter period, causing adverse effects for the main agricultural season. Further, moisture losses due to increasing evapotranspiration rates indicate problems for the annual water budget and groundwater recharge. The per capita blue water availability falls below a minimum threshold of 500 m3 per year, denoting a high regional vulnerability to increasing water scarcity assuming a no-response scenario. Regional development focusing on the water-intense sectors of agriculture and tourism appears to be at risk. Institutional capacities and policies need to address the problem, and the prompt implementation of innovative water production and efficiency measures is recommended.

Description: Due to greater demands for hydrocarbons and improvements in drilling technology, development of oil and natural gas in some regions of the United States has increased dramatically. A 1.4 ha natural gas well pad was constructed in an intermittent stream channel at the Alto Experimental Watersheds in East Texas, USA (F1), while another 1.1 ha well pad was offset about 15 m from a nearby intermittent stream (F2). V-notch weirs were constructed downstream of these well pads and stream sedimentation and water quality was measured. For the 2009 water year, about 11.76 cm, or almost 222% more runoff resulted from F1 than F2. Sediment yield was significantly greater at F1, with 13,972 kg ha−1 yr−1 versus 714 kg ha−1yr−1 at F2 on a per unit area disturbance basis for the 2009 water year. These losses were greater than was observed following forest clearcutting with best management practices (111–224 kg ha−1). Significantly greater nitrogen and phosphorus losses were measured at F1 than F2. While oil and gas development can degrade surface water quality, appropriate conservation practices like retaining streamside buffers can mitigate these impacts.

Description: Enzymatic modification of polyethersulfone (PES) membranes has been found not only feasible, but also an environmentally attractive way to vary surface properties systematically. In this paper, we summarize the effect of modification layers on protein adsorption and bacterial adhesion on PES membranes and surfaces. The enzyme laccase was used to covalently bind (poly)phenolic acids to the membrane, and compared to other membrane modification methods, this method is very mild and did not influence the mechanical strength negatively. Depending on the conditions used during modification, the modification layers were capable of influencing interactions with typical fouling species, such as protein, and to influence attachment of microorganisms. We also show that the modification method can be successfully applied to hollow fiber membranes; and depending on the pore size of the base membrane, proteins were partially rejected by the membrane. In conclusion, we have shown that enzymatic membrane modification is a versatile and economically attractive method that can be used to influence various interactions that normally lead to surface contamination, pore blocking, and considerable flux loss in membranes.

Description: Land management and natural resource public policy decision-making in the United States can benefit from two resource damage/recovery concepts: ecosystem service (ES) and critical load (CL). The purpose of this paper is to suggest an integrated approach to the application of ES and CL principles for public land management and natural resource policy decision-making. One well known example that is appropriate for ES and CL evaluation is examined here: the acidification of soil and drainage water by atmospheric deposition of acidifying sulfur and nitrogen compounds. A conceptual framework illustrates how the ES and CL approaches can be combined in a way that enhances the strengths of each. This framework will aid in the process of translating ES and CL principles into land management and natural resource policy decision-making by documenting the impacts of pollution on environmental goods and services that benefit humans.

Description: Green roofs, which have been used for several decades in many parts of the world, offer a unique and sustainable approach to stormwater management. Within this paper, evidence is presented on water retention for an irrigated green roof system. The presented green roof design results in a water retention volume on site. A first principle mass balance computer model is introduced to assist with the design of these green roof systems which incorporate a cistern to capture and reuse runoff waters for irrigation of the green roof. The model is used to estimate yearly stormwater retention volume for different cistern storage volumes. Additionally, the Blaney and Criddle equation is evaluated for estimation of monthly evapotranspiration rates for irrigated systems and incorporated into the model. This is done so evapotranspiration rates can be calculated for regions where historical data does not exist, allowing the model to be used anywhere historical weather data are available. This model is developed and discussed within this paper as well as compared to experimental results.