Optimising value from the soft re-use of brownfield sites.

Soft re-use of brownfields describes intended temporary or final re-uses of brownfield sites which are not based on built constructions or infrastructure ('hard' re-use). Examples of soft re-uses include the creation of public green space. These are essentially uses where the soil is not sealed. Often the case for soft re-use of brownfields has not been easy to demonstrate in strictly financial terms. The purpose of this paper is to describe a value based approach to identify and optimise services provided by the restoration of brownfields to soft re-uses, on a permanent or interim basis. A 'Brownfield Opportunity Matrix' is suggested as means of identifying and discussing soft restoration opportunities. The use of 'sustainability linkages' is suggested as a means of understanding the sustainability of the services under consideration and providing a structure for the overall valuation of restoration work, for example as part of design or option appraisal processes, or to support the solicitation of interest in a project.

Geochemistry and flooding as determining factors of plant species composition in Dutch winter-flooded riverine grasslands.

Dutch water policy aims for more frequent, controlled flooding of river valley floodplains to avoid unwanted flooding elsewhere; in anticipation of increased flooding risks resulting from climate changes. Controlled flooding usually takes place in winter in parts of the valleys which had not been subject to flooding in the last decades. It may thus affect existing nature with its conservation values. The goal of this study was to clarify the geochemical and hydrological factors determining plant species composition of winter-flooded river valley grasslands. A correlative study was carried out in 43 sites in 13 Dutch river valley floodplains, with measurements of flooding regime, vegetation composition, soil nutrients and soil pH status. With the use of canonical correspondence analysis (CCA) the plant species composition was investigated in relation to the geochemical variables and the winter winter-flooding regime. We found that the distributions of target species and non-target species were clearly correlated with geochemical characteristics and flooding regime. Clustering of sites within the CCA plots has led us to distinguish between four types of winter flooding in our areas: floodplains with (a) accumulating rain water, (b) low groundwater levels flooded with river water, (c) discharging groundwater and (d) high groundwater levels flooded with river water. Our major conclusions are (1) the winter groundwater level of winter-flooded grasslands was important for evaluating the effects of winter flooding on the geochemistry and plant species composition, and (2) winter winter-flooding effects were largely determined by the nature of the flooding. A high frequency of flooding particularly favoured a small set of common plant species. In areas with groundwater seepage, winter flooding may provide geochemical conditions suitable for diverse vegetation types with rare species. Rainwater flooded sites appeared less suitable for most target species.