Inventory of river restoration measures: effects, costs and benefits

tom.buijse@deltares.nl — Thu, 16 Jan 2014 10:38:42 +0000

Review on costs and benefits of river restoration. Data were collected in a database to empirically investigate the costs of river restoration measures throughout Europe. Also, a summary of restoration planning and the specific measures which can inform the future development of cost-benefit analysis and their application were introduced. A non-exhaustive review of peer-reviewed literature and technical reports was conducted to elicit the effects of individual measures, providing a basis for the analysis of restoration benefits.

The non-exhaustive review of river restoration measures showed that it is extremely difficult to predict the impacts of specific river restoration measures on a European-level. The river type, based on geomorphological and functional process units, as well as the specific anthropogenic pressures are relevant for choosing suitable restoration measures. Practical limitations such as land availability, project budget, and/or stakeholder consent limit the spatial extent to which rivers can be restored. Programmes of Measures should address the type and scale of pressures in a river basin, provide long-lasting improvements, and be robust against the impacts of climate change. Independent of the type of restoration measures, considering the hydrogeomorphological processes affecting a river restoration site and implementing this information into the project design is critical to elicit the maximum ecological benefits from measures (REFORM D5.1).

Many successful river restoration measures have been reported, which support improvements to hydrology, hydromorphology, water chemistry, biota, or ecosystem services. The findings of the non-exhaustive literature review on the ecological benefits of restoration measures to the WFD Biological Quality Elements macrophytes, macroinvertebrates, and fish are presented. Although this type of clear-cut and generalized information is useful to river managers and decision makers, it does not encompass the full spectrum of complexity and uncertainty surrounding restoration impacts. The response of biota to habitat improvements may be confounded or delayed by many factors, including: migration barriers, the lack of a colonizing source population, the isolation of restored habitat reaches, long-term recovery processes, the creation of inappropriate/unsuitable habitat conditions, or biotic interference resulting from competition, predation, or invasive species. Also, the impacts of large-scale pressures which are not addressed by reach-scale restoration can override the hydromorphological improvements made by reach-scale restoration measures (e.g., catchment land use, water quality, missing source populations, etc.). Careful treatment of the environmental framework conditions and site-specific socio-economic constraints is necessary to elicit the ecological benefits of river restoration.

The cost database created was designed to gather data on the costs of the reported measures while also collecting sufficient information to enable marginal cost-benefit and cost-effectiveness analyses by way of statistics on effectiveness and monetary benefits (REFORM D5.2, forthcoming). The cost database contained cost data for 766 restoration projects from Germany (n=454), Spain (n=228), the United Kingdom (n=54), and the Netherlands (n=30). Cost data were reported as total investment cost per unit for the implementation of individual measures. Fifty-nine percent of the data (all German data) were estimated costs (n=454), while the remaining 41% from ES, NL, and the UK were actual reported total unit costs from restoration projects (n=312). To provide a finer spatial resolution to the restoration measures in the database and to enable a scaling-up of costs, effects, or benefits (D5.2, forthcoming), project data were assigned a river typology, based on the river types developed within REFORM D2.1.

Most of the projects in the database were conducted in single thread, alluvial gravel or sand rivers. The majority of the hydromorphological measures reported in these countries concern in-channel habitats, floodplains, and longitudinal connectivity. Measures dealing with sedimentation and river planform (depth and width variation) also make up a noteworthy percentage. The four countries included in this study reported very different restoration portfolios, and the types of measures implemented in each country do not necessarily reflect the state of their river systems.

In all cited stated preference elicitation studies, the economic benefits of the hydro-morphological river restoration are proxied through the environmental benefits and services provided by restored river ecosystems and/or riparian zones. As a rule, a restoration project is considered as a bundle of use and non-use ecosystem services, which makes it very difficult to extract separate values for particular services or even their groups. The most commonly considered services (benefits) are higher wildlife and aquatic life diversity, provision of drinking water, improved water and air quality, flood protection, carbon sequestration, erosion protection, better river appearance and recreational amenities of a riparian forest, better possibilities for swimming, boating, and fishing activities, and nitrate and phosphorus cycling and retention. The majority of reviewed studies, 23 out of 30, assume that the main beneficiaries of river restoration are local households and use different forms of contingent valuation studies or discrete choice experiments to elicit their valuation of the restoration projects.

1.4 Inventory of restoration costs and benefits.pdf

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D1.4 Inventory of the cost of river degradation and the socio-economic aspects and costs and benefits

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Policy Brief:

D 1.1 Review on eco-hydromorphological methods

tom.buijse@deltares.nl — Wed, 23 Jan 2013 12:13:11 +0000

Several ecological and hydromorphological assessment methods have been developed in different countries during the last years, with notable differences in terms of aims, scales, and approaches. In many cases, strengths and limitations of the different types of methods are not yet sufficiently known, although they are widely used in some European countries. The objective of this report is to provide an extensive overview of the eco-hydromorphological assessment methods that are available for the implementation of the WFD and to identify strengths, limitations, gaps, possible integration of different approaches, and needs for future progress. The main emphasis is on ‘hydromorphological assessment methods’, i.e., methods and procedures developed and used to characterize hydromorphological conditions and classify the status of streams and rivers, including a review of indicators and parameters used within this context.

For this review, five broad categories of hydromorphological assessment methods have been distinguished: (1) Physical habitat assessment; (2) Riparian habitat assessment; (3) Morphological assessment; (4) Hydrological regime alteration assessment; (5) Longitudinal fish continuity assessment. The first stage was to review the general characteristics of a total of 139 methods (European and non-European). For each category, the main information concerning each method has been summarized, allowing for a comparative analysis of the methods. The second stage focused on a selection of European methods (in total 21), i.e., those methods that have been formally approved or that are commonly used (although without formal approval) by European countries for the WFD implementation. For each method, the scope, characteristics, recorded features and indicators, processes and strengths have been summarized. Ecological assessment methods in use for determining the ecological status of European rivers were also reviewed. The review covers the methods that are being used by the EU countries to monitor ecological status. A total of 91 methods were considered, covering fish fauna, macrophytes, benthic diatoms, and benthic invertebrates from 27 European countries.

A series of strengths and limitations have been identified. The main gap is the insufficient consideration of physical processes in the assessment of hydromorphological conditions. With few exceptions, hydromorphological analysis adopted in most EU countries is limited to a physical habitat assessment, which is only one component of an overall hydromorphological evaluation. This is an important limitation because a characterization of physical habitats alone does not provide sufficient understanding of alterations or their causes and of pressure-responses (i.e., causes-effects), that are extremely important for the implementation of rehabilitation measures.

We recommend developing a framework for integrated hydromorphological analysis, where the morphological and hydrological components are key parts of the evaluation along with classification of hydromorphological state and quality, while physical habitat and longitudinal fish continuity should represent additional components that are useful for a complete characterization of hydromorphological conditions.

The review of existing ecological methods has also identified some additional limitations, particularly in their ability to respond to hydromorphological pressures. Methods using fish fauna, macrophytes, and benthic invertebrates are not pressure-specific; they will detect effects of multiple pressures, including hydromorphological pressures. Little information is available on the specific response of individual methods to hydromorphological pressures. Supplementary information characterizing the pressures (hydromorphological and other) is required to identify problems and to plan appropriate measures.

1.1_REFORM_DeliverableD1.1_V8_Final.pdf

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D1.1 Review on ecohydromorphological methods

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Final

REFORM - Review

Inventory of river restoration measures: effects, costs and benefits

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Policy Brief:

D 1.1 Review on eco-hydromorphological methods

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