Exploring the utility of Bayesian Networks for modelling cultural ecosystem services: A canoeing case study.

Modelling cultural ecosystem services is challenging as they often involve subjective and intangible concepts. As a consequence they have been neglected in ecosystem service studies, something that needs remedying if environmental decision making is to be truly holistic. We suggest Bayesian Networks (BNs) have a number of qualities that may make them well-suited for dealing with cultural services. For example, they define relationships between variables probabilistically, enabling conceptual and physical variables to be linked, and therefore the numerical representation of stakeholder opinions. We assess whether BNs are a good method for modelling cultural services by building one collaboratively with canoeists to predict how the subjective concepts of fun and danger are impacted on by weir modification. The BN successfully captured the relationships between the variables, with model output being broadly consistent with verbal descriptions by the canoeists. There were however a number of discrepancies indicating imperfect knowledge capture. This is likely due to the structure of the network and the abstract and laborious nature of the probability elicitation stage. New techniques should be developed to increase the intuitiveness and efficiency of probability elicitation. The limitations we identified with BNs are avoided if their structure can be kept simple, and it is in such circumstances that BNs can offer a good method for modelling cultural ecosystem services

Does it help? Testing the usefulness of a tool to aid Integrated Catchment Management

AbstractIntegrated Catchment Management (ICM) advocates the consideration of multiple management objectives together in the decision making process rather than as unconnected separate issues. To deliver ICM, many integrated models are being created to be used as tools that predict how catchment interventions affect multiple management objectives. It is generally assumed that if applied, these tools will improve decision making. In this paper we discuss how this assumption can be tested, and then present preliminary work to do just that. A tool was created to predict how weir modifications such as fish passes affect multiple river ecosystem services in the Don Catchment, UK. These ecosystem services included eel productivity, conservation of an endangered and spread of an invasive crayfish, hydroelectricity generation and river quality for canoeing. In an experiment this tool was used to make hypothetical management decisions, and the quality of the decision making was compared to a control decision making process representative of current practice in the catchment. The experiment was designed to evaluate decision quality by gauging efficiency and moderateness of decisions made, and by measuring the confidence and knowledge gained by participating decision makers. Preliminary results indicate that users of the tool learnt less information about the environmental issue of weir impoundment compared to the more conventional approach. If this effect is common when decision support tools are used to support ICM, then it has implications for how they are designed and utilised in the future

A low cost method to detect polluted surface water outfalls and misconnected drainage

Sewer misconnections lead to discharge of wastewater direct to rivers and streams. They are difficult to detect due to their intermittent discharges and the wide range of compounds which can be discharged. Optical brighteners are strong indicators of the presence of sewer misconnection discharge in surface water sewers, representative of many components of misconnections, and easily identified. The authors have developed and tested a promising method to identify optical brighteners in sewer systems using inexpensive passive samplers and a simple analysis method. The method is used to identify large areas of four sewer systems which are polluted with misconnection discharge. Limited validation shows that the method successfully indicated diffuse pollution in the surface water sewer system

The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes

Stream power is a measure of the main driving forces acting in a channel and determines a river's capacity to transport sediment and perform geomorphic work. Recent digital elevation models allow the calculation of channel gradient and consequently stream power at unprecedented spatial resolution, opening promising and novel opportunities to investigate river geomorphic processes and forms. The present paper investigates the suitability of map-derived information on total and specific stream power (SSP) to identify dominant processes within the channel (i.e. erosion, transport or deposition). SSP has been already used to identify a threshold for channel stability. This paper tests this knowledge and investigates whether or not attributes of stream power profiles are statistically correlated with distinctive field morphological forms. Two gravel bed single-thread English rivers are used as case studies, the Lune and the Wye. Available deposition and erosion features surveyed in the field from 124 different locations are used to classify channel reaches as erosion, transport or deposition dominated. Meaningful patterns emerge between the stream power attributes and the field-based channel classification. An SSP threshold, which erosion is triggered, compares favourably with the ones in the literature. Information about upstream stream power profiles helps to determine the dominant processes. The joint configuration of local and upstream stream power information uniquely classifies reaches into four classes of different sensitivity to erosion and deposition

Finding lost streams and springs captured in combined sewers: A multiple lines of evidence approach

Some streams and springs have been historically and intentionally captured into combined sewer systems. This is a source of clean baseflow to combined sewers and wastewater treatment works that, unlike groundwater, infiltration-inflow through pipe cracks and defective joints, has not been widely considered by the UK water industry. This study presents the first formal methodology, using multiple lines of evidence, to locate lost streams and springs and identify where they have been captured into the combined sewers. In a UK case study, approximately half the total stream length and over 100 natural springs have been apparently lost and could be flowing into the combined sewers. Evidence has demonstrated the suitability of tests to indicate captured flow in sewers, and has confirmed several streams and springs flowing into combined sewers

Assessing Risk from DNAPLs in Fractured Aquifers

Chlorinated solvents are among the most widespread pollutants of groundwater. As DNAPLs (dense nonaqueous phase liquids), they can move rapidly and in complex patterns through fractures to reach and contaminate large volumes of aquifer, and then dissolve to cause significant pollution of groundwater. However, clean-up of DNAPLs in fractured rocks is virtually impossible and certainly expensive. Risk assessment should be used to decide whether the pollution is serious enough to justify major expenditure on clean-up or containment. A key aspect of risk assessment for DNAPLs in fractured aquifers is to understand how deep they are likely to have penetrated through the fracture network. This paper addresses two aspects of such predictions: measuring fracture apertures in situ and the connectivity of fracture networks with respect to DNAPLs. Fracture aperture is an in-situ field technique that has been developed and implemented to measure aperture variability and NAPL entry pressure in an undisturbed, water-saturated rock fracture. The field experiment also provided the opportunity to measure the wetting phase relative permeability at residual non-wetting phase saturation. The RADIO (Radial Aperture Determination by the Injection of Oil) method employs a constant rate injection of a non-toxic NAPL into a fracture isolated by a double packer array. The method was applied at the field site in Scotland, and measured apertures out to ~5m from the borehole. It showed that hydraulic aperture (from packer tests) was a poor estimator of the controlling aperture for DNAPL movement. This is the first time such large-scale aperture measurements have been made, and the technique is the first which can provide useful aperture estimates for risk analysis of DNAPL movement.Network connectivity is a fundamental property of the fracture system. DNAPL connectivity extends the concept to take account of the fluid properties

Integrated modelling for Sustainability Appraisal of urban river corridors: Going beyond compartmentalised thinking

AbstractSustainability Appraisal (SA) is a complex task that involves integration of social, environmental and economic considerations and often requires trade-offs between multiple stakeholders that may not easily be brought to consensus. Classical SA, often compartmentalised in the rigid boundary of disciplines, can facilitate discussion, but can only partially inform decision makers as many important aspects of sustainability remain abstract and not interlinked. A fully integrated model can overcome compartmentality in the assessment process and provides opportunity for a better integrative exploratory planning process.The objective of this paper is to explore the benefit of an integrated modelling approach to SA and how a structured integrated model can be used to provide a coherent, consistent and deliberative platform to assess policy or planning proposals. The paper discusses a participative and integrative modelling approach to urban river corridor development, incorporating the principal of sustainability. The paper uses a case study site in Sheffield, UK, with three alternative development scenarios, incorporating a number of possible riverside design features. An integrated SA model is used to develop better design by optimising different design elements and delivering a more sustainable (re)-development plan. We conclude that participatory integrated modelling has strong potential for supporting the SA processes. A high degree of integration provides the opportunity for more inclusive and informed decision-making regarding issues of urban development. It also provides the opportunity to reflect on their long-term dynamics, and to gain insights on the interrelationships underlying persistent sustainability problems. Thus the ability to address economic, social and environmental interdependencies within policies, plans, and legislations is enhanced

A Habitat Assessment Approach to the Management of Groundwater Dominated Rivers

The Instream Flow Incremental Methodology (IFIM) using the Physical Habitat Simulation (PHABSIM) system, has seen increasing application to the assessment of changes in aquatic habitats in the UK over the last 10 years. In particular, the model has been applied operationally to chalk streams (e.g. the Rivers Allen and Piddle) in southern England for the alleviation of low ¯ow (ALF) problems. More recently, the model has also been used to examine the e�ect of changes in channel morphology upon aquatic habitats, such as those that occur during ¯ood defence, or river channel restoration, schemes. The paper outlines some of the issues related to the application of the model to groundwater dominated rivers, such as chalk streams, and provides examples of the application of the model to a water resource issue and to assess a habitat restoration scheme. The paper also reports on three areas of recent research to improve the methodology: (1) choice of representative study sites and habitat variation at the reach and sector scale; (2) modelling of time series and interpretation of alternativewater management regimes; and (3) the development of rapid assessment techniques based upon the transfer of standardised relationships between available habitat and discharge