Dennis Collentine

CATCH: decision support for stakeholders in catchment areas

Policy proposals for the management of water resources need to take into account two emerging themes: public involvement in the development of resource use policy and water management on a catchment level. The CATCH-model, a decision support system for catchment-based water management, builds on the use of ‘discourse and deliberation’ within stakeholder groups to define relevant socio-economic parameters and the relationships between these parameters. The sets of matrices that describe these parameters and their interrelation serve as the basis for evaluation of alternative management strategies and evaluation of specific measures for improving water quality.

Composite market design for a Transferable Discharge Permit (TDP) system

Abstract There has been a great deal of interest in addressing water quality issues through the use of Transferable Discharge Permit (TDP) systems. Unfortunately, the attempts to start up permit markets that are able to exploit abatement cost differences between sources have not met with the success expected. Two of the reasons for the lack of success have been the problem of transaction costs and in the case of non-point sources (NPS), undefined property rights. The composite market design is a proposal for a TDP system that specifically includes agricultural non-point source (NPS) discharges and addresses both property rights and transaction cost problems. The composite market consists of three interrelated markets each serving a particular function. The two primary markets are coordinated through price information that makes it possible for a catchment-based authority to issue (sell) permits based on the marginal cost of abatement. When the composite market is mature, the total number of permits issued corresponds to a cap on discharges allowed in the catchment. The structure of the composite market allows this system to be phased in over time with existing institutions and limited demands on financing.

Realising the potential of natural water retention measures in catchment flood management: trade-offs and matching interests

Natural Water Retention Measures (NWRM) are a multi-functional form of green infrastructure that can play an important role in catchment-scale flood risk management. While green infrastructure based on natural processes are increasingly recognized as being complementary to traditional flood control strategies based on grey infrastructure in urban areas, there are a number of outstanding challenges with their widespread uptake. At a catchment scale, it is widely accepted that NWRM in upstream areas based on the concept of “keeping the rain where it falls” can help reduce the risk of downstream flooding by enhancing or restoring natural hydrological processes including interception, evapotranspiration, infiltration and ponding. However, both the magnitude of flood risk reduction and the institutional structures needed for widespread uptake of NWRM are inadequately understood. Implementing NWRM can involve tradeoffs, especially in agricultural areas. Measures based on drainage management and short rotation forestry may help “keep the rain where it falls” but can result in foregone farm income. To identify situations where implementation of NWRM may be warranted, an improved understanding of the likely reductions in downstream urban flood risk, the required institutional structures for risk management and transfer and mutually acceptable farm compensation schemes are all needed.

Phase-in of nonpoint sources in a transferable discharge permit system for water quality management: setting permit prices.

Abstract The composite market design is a proposal for a transferable discharge permit system that specifically includes agricultural non-point-source dischargers and addresses both property rights and transaction cost problems. The first step to implementation of a composite market scheme is the estimation of a supply curve for abatement measures in the catchment area. Estimation is performed by combining costs with modeled loss reductions from selected best management practices and then using this information to estimate the supply curve for abatement, which in turn can then be used to set permit prices. The Rönneå catchment in southern Sweden is used as a pilot study area for making this type of estimate. Costs for existing measures that reduce nutrient losses from farmland (catch crops and spring planting) are based on existing programs financed by the Swedish Agricultural Board. A set of supply curves is calculated for these measures using retention estimates for seven subcatchments and three soil types in the area. Although existing information is sufficient to calculate partial supply curves and may be used to set permit prices, additional measures should be included as well as an increased number of variables for differentiating site specific reduction costs.

CATCH: A Method for Structured Discussions and a Tool for Decision Support

Human activities have led to the overexploitation and pollution of water resources. The Water Framework Directive (WFD, 2000/60/EG) has been created to ensure the sustainable use of and impact on water resources. An explicit component in achieving the goals outlined in the WFD is the participation of stakeholders in the management of these resources. Involving stakeholders is an important step to ensure that catchment management plans take into consideration local experience in the development of these plans and the impact of the plans on local interests. Water resource stakeholders have different sets of preferences. For example, some stakeholders may be interested in the use of water resources for recreational purposes, while other stakeholders may use water for food production or as a recipient for waste products. These various services provided by water resources demand different qualities and quantities of water; in many instances, these interests may be conflicting where the provision of one particular service quality or quantity precludes the provision of other services (1, 2). Implementation of the WFD is now on the agenda for national authorities in EU member states. One of many the questions that arise are related to how the mandated management plans may achieve the socioeconomic and ecological sustainable use of water resources and at the same time promote stakeholder participation in management decisions. Several studies have found that knowledge with respect to both the resource and the action of other interest groups leads to a more sustainable use of the resource (3, 4). An open dialogue among stakeholders may resolve potential areas of conflicts between interest groups before they become a problem. The decision support tool CATCH is a model for structuring a dialogue as a method for stakeholder participation in the management process. This discussion of issues in strategic settings facilitates implementation of the WFD at a catchment level (5, 6).

Targeting critical source areas for phosphorus losses: Evaluation with soil testing, farmers’ assessment and modelling

Abstract Diffuse phosphorus (P) losses from arable land need to be reduced in a cost-efficient way, taking into account their temporal and spatial variability. This study, based on 16 farms across southern Sweden, examined possibilities for identifying critical source areas for P losses based on the combined results of high-resolution erosion modelling, independent risk assessments by farmers, soil survey and SWOT analysis performed by farmers. Statistically significant differences in dissolved P release were found between soil P test classes in the studied area, whereas soil textural classes and not P content governed potential mobilisation of soil particles and unreactive P. Spatial comparison of problem areas identified by farmers and modelled features showed that the modelled erosion pathways intersected 109 in a total of 128 (85%) observed problem areas. The study demonstrates the value in involving farmers in the identification of critical source areas in order to select and support implementation of effective countermeasures.

Ecosystem C and N dynamics affected by a modified spring barley trait with increased nitrogen use - a simulation case study

ABSTRACT To what extent might a crop with increased plant N uptake efficiency and/or N demand increase plant biomass and soil carbon storage, decrease N leaching, and reduce the need for N fertilisation? This was assessed for a fertilised sandy loam site in central Sweden cultivated with spring barley for a four year period using a process based crop and soil simulation model (SOILN) calibrated to fit observations of field experiments with non-modified crops. Crop properties were changed in accordance with previous model applications to other crops with higher N uptake and utilisation efficiencies, to resemble potential effects of breeding. For the modified crops a doubling of daily uptake efficiency of soil mineral N and/or increase of radiation use efficiency by 30%, increased plant biomass by 3%–30%, decreased N leaching by 1%–30% and increased soil organic carbon (SOC) content by 1–12 g C m−2 year−1. The larger changes were mainly due to increased uptake efficiency. Fertilisation of the modified spring barley crop could be reduced while still producing the same plant biomass as the non-modified crop. The plant biomass to N leaching ratio of the modified crops increased. The simulated changes in plant biomass and SOC were sensitive to weather conditions suggesting that in situ experiments would need to cover a large range of weather conditions to evaluate the performance of new crop traits under climatic variability. The study suggests a strong need that field experiments are accompanied with model applications, when exploring the potential of the modified crops under variable conditions.

Nitrogen leaching and soil organic carbon sequestration of a Barley crop with improved N use efficiency – A regional case study

ABSTRACT The potential of modified spring barley crops with improved nitrogen (N) use efficiency to reduce nitrogen (N) leaching and to increase soil organic carbon (SOC) storage was assessed at the regional scale. This was done using simulation model applications designed for reporting according to the Helcom (Helsinki Commission) and Kyoto protocols. Using model simulations based on modified crops N dynamics and SOC were assessed for three agro-ecological regions (latitudes ranging 55°20′–60°40′ N) in Sweden over a 20-year period. The modified N use properties of spring barley were implemented in the SOILNDB model (simulating soil C, N, water and heat, and plant N dynamics) by changing the parameters for root N uptake efficiency and plant N demand within a range given by previous model applications to different crops. A doubling of the daily N uptake efficiency and increased N demand (by ca 30%) reduced N leaching by 24%–31%, increased plant N content by 9%–12%, depending on region. The effects of the modified crop on SOC was simulated with the ICBM model, resulting in an increased SOC content (0–25 cm depth) by 57–79 kg C ha−1 y−1. The results suggest that a modified crop might reduce N leaching from spring barley area, in a range similar to the targets of relevant environmental protection directives, a result which held more in the northern than southern regions. The simulated SOC increase on a hectare basis was highest for the central region and least for the most northern region. For the total agricultural area the share of spring barley area was small and more crops would need to be modified to reach the emission reduction targets.