Using fluvial geomorphology to inform integrated river basin management

Recent years have seen a trend towards larger scale, multidisciplinary approaches to river management. This reflects changes in policy and legislation, particularly the drive towards integrated river basin management as required by the EC Water Framework Directive. Fluvial geomorphology is a discipline that links the physical function of the river to its ecological status, and thus has a fundamental role to play in future river basin management. This is becoming more widely recognised at a project level, as well as nationally and internationally. This paper will demonstrate, using the case study of the Axe Catchment Fluvial Audit, how fluvial geomorphology can be successfully applied to inform river basin management. The outputs from the project are described together with some of the key limitations and lessons learned.     

Geo-referenced modeling of zinc concentrations in the Ruhr river basin (Germany) using the model GREAT-ER

Zinc enters surface waters from a variety of different emission sources. The geo-referenced model GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) was applied to simulate spatially resolved zinc concentrations in the Ruhr river basin. The model links geo-referenced emissions (loads) to concentrations at local and regional scales and allows for evaluating the relative importance of emission sources. For each emission from point sources (household, industry, urban runoff) and non-point sources (agriculture, natural background), zinc loads were independently estimated using appropriate reference parameters (number of inhabitants, surface area drained, agricultural area, zinc ore regions). For point emissions from industry and mine drainage loads were taken directly from available data compilations. Simulated total zinc concentrations agree well with monitoring data. The strength of the modeling tool became evident from the unequivocal link that could be established between observed surface water concentrations and the large zinc input from geogenic sources and abandoned mines. These emission sources are regional characteristics of the Ruhr river basin and due to the fact that some regions are relatively rich in zinc ore, which was extracted over a long period of time. Although most of these emissions occur in the upper part of the catchment, they contribute to approximately one-third to the zinc load at the confluence with the Rhine River. Urban emissions from household, traffic (road) and buildings (roof) were shown to be responsible for approximately half of the concentration in the Ruhr at the confluence with the Rhine River.     

A new mode of river basin management in South Korea

This study aims to explore a new mode of river basin management in South Korea by evaluating the current river basin management system and taking lessons from the British and French cases. This research is based on literature reviews and interviews in the United Kingdom, France and South Korea. The British case emphasizes the importance of regulatory framework and limitations of public participation. The French experience epitomizes the empowerment of river basin organizations. The new system in South Korea includes an enactment of water law, a set-up of the National Water Council, the River Basin Authorities and the River Basin Committees. The new model will not be established soon but needs to take a step-by-step approach to minimize social conflicts, accommodate diverse opinions in society and satisfy a variety of demands.     

Institutional challenges for integrated river basin management in Langat River Basin,Malaysia

This paper reports on a study of the institutional challenges and factors affecting policy processes and outcomes of integrated river basin management (IRBM) in the Langat River Basin (LRB), Malaysia. A case study approach using institutional analysis and development (IAD) framework was used, and field observations and interviews with local stakeholders of LRB were carried out. The study revealed that polycentric institutional arrangements under the Federal administration are likely capable of coordinating and integrating river basin management by extending the scope of an iterative learning through participation of individual stakeholder at the lowest appropriate level. There should also be an iterative learning mechanism within the interorganizational network for IRBM in LRB. This learning approach is conceptualized as social learning and accordingly a framework is recommended for LRB. The findings of this study would be useful to those who are concerned with successful IRBM implementation in LRB and elsewhere.     

Agriculture-induced increase in nitrate concentrations in stream waters of a large Mediterranean catchment over 25 years (1981–2005)

Anthropogenic activities influence past and present nitrate levels recorded in European stream waters, posing a threat to aquatic biota and human beings. Scarce information on temporal trends of nitrate concentration and its causes is available for Mediterranean catchments. This study presents the evolution of nitrate concentrations over 25 years in stream waters of the Ebro River Basin (Spain), a large Mediterranean catchment involving 85,566 km². Nitrate concentration increased with time in 46% of the 65 sites involved in the study. Agricultural cover of 30 hydrologically independent sub-catchments was the main land use related to nitrate concentration (R² = 0.69). Throughout the 25 year-period, the sites showing increased nitrate concentrations with time (trend sites) also presented an enhanced influence of agricultural cover on nitrate concentrations along the time frame of the study. As a result of these temporal changes, at the end of the studied period nitrate concentrations in stream waters responded similarly to agricultural cover in both trend and non-trend sites, showing non significant differences in the slope of the resultant regression models. At this time, agricultural cover explained 82% of the variability found in nitrate levels. If these trends remain unchanged, in 2015 many of the water bodies considered in this study would not comply with the requirements of the European Union Water Framework Directive (WFD). Therefore management decisions, mainly associated to agricultural practices, should be implemented as soon as possible at the catchment level to meet WFD objectives.     

River health assessment in peri-urban landscapes: an application of multivariate analysis to identify the key variables

An array of river health assessment approaches and water quality variables have been suggested in the past for assessing the level of river health. However, the selection of suitable variables to be monitored for the assessment remains ambiguous and often it is not practical to monitor all the suggested variables. In this study, we employ a multivariate data reduction technique, called Factor Analysis (FA), to identify the key river health variables for a peri-urban river system, viz., the Hawkesbury-Nepean River system in New South Wales, Australia. Out of 40 water quality variables included in the analysis, the FA identified nine key variables, under three varifactors (VFs), explaining 50% of the variance in the river water quality. Variables in the first, second and third VFs revealed anaerobic conditions, microbial quality and effects of eutrophication in the Hawkesbury-Nepean River. Thus, the present work shows a notable reduction in the number of variables and the application of FA for identification of key variables was found promising. The finding of this study has potential application in designing a cost-effective river health monitoring program by reducing the number of variables to be monitored in a peri-urban situation. It can also assist in partitioning variables according to their unique contribution to the total variance.     

Developing a new method for spatial assessment of drought vulnerability (case study: Zayandeh‐Rood river basin in Iran)

The paper presents an approach to spatially representative depiction for assessing the vulnerability of central Iran's Zayandeh‐Rood river basin to drought using multiple indicators. Drought conditions prevailed in the study basin from 2002 to 2007, with an annual rainfall deficiency of 45 to 55%. Multi‐attribute decision making (MADM) methods develop a framework to evaluate the relative priorities of drought assessment based on a set of preferences, criteria and indicators. The proposed MADM process uses well‐known techniques for product weights analytic hierarchy process (AHP) and order preference (TOPSIS). These indicators include the Standard Precipitation Index (SPI), water demand, the Palmer Drought Severity Index (PDSI) and the Groundwater Balance and Surface Water Supply Index (SWSI). Indicators' spatial information was categorised in layers prepared in the spatial domain using a geographic information system (GIS). The alternatives were ranked and presented using TOPSIS. Results show that the proposed method was highly effective in representing assessments of drought vulnerability.     

Evaluation of wastewater nitrogen transformation in a natural wetland (Ulaanbaatar, Mongolia) using dual-isotope analysis of nitrate

The Tuul River, which provides water for the daily needs of many residents of Ulaanbaatar, Mongolia, has been increasingly polluted by wastewater from the city's sewage treatment plant. Information on water movement and the transformation of water-borne materials is required to alleviate the deterioration of water quality. We conducted a synoptic survey of general water movement, water quality including inorganic nitrogen concentrations, and isotopic composition of nitrogen (δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻, and δ¹⁵N-NH₄⁺) and water (δ¹⁸O-H₂O) in a wetland area that receives wastewater before it enters the Tuul River. We sampled surface water, groundwater, and spring water along the two major water routes in the wetland that flow from the drain of the sewage treatment plant to the Tuul River: a continuous tributary and a discontinuous tributary. The continuous tributary had high ammonium (NH₄⁺) concentrations and nearly stable δ¹⁵N-NH₄⁺, δ¹⁵N-NO₃⁻, and δ¹⁸O-NO₃⁻ concentrations throughout its length, indicating that nitrogen transformation (i.e., nitrification and denitrification) during transit was small. In contrast, NH₄⁺ concentrations decreased along the discontinuous tributary and nitrate (NO₃⁻) concentrations were low at many points. Values of δ¹⁵N-NH₄⁺, δ¹⁵N-NO₃⁻, and δ¹⁸O-NO₃⁻ increased with flow along the discontinuous route. Our results indicate that nitrification and denitrification contribute to nitrogen removal in the wetland area along the discontinuous tributary with slow water transport. Differences in hydrological pathways and the velocity of wastewater transport through the wetland area greatly affect the extent of nitrogen removal.