Bias and Purpose

4.1.4 Bias and Purpose

4.1.4.1 Overview

This bias and purpose section is intended to establish the roles that the SFRB was first designed for as well as its current uses. It should be clear that not all SFRB are used for their original purpose; for example, in Scotland there are many former industrial impoundments and disused drinking water supply reservoirs. These structures are typically somewhat neglected, which then results in a high biodiver- sity, making them attractive to the local communities who now use them as nature reserves or for other recreational activities such as walking, bird watching, and fishing. It is these evolutions and changes in function with time that are captured by this section of the survey method.

4.1.4.2 Dominant Hydraulic Purpose

A SFRB with a dominant hydraulic purpose is typically either wet or dry. Wet SFRB are purpose-built water storage reservoirs for drinking water or for the regu- lar supply of water to industrial processes. Dry types of SFRB with a predomi- nantly hydraulic function are those built for long return period flood events, which may be part of an integrated system of flood defense reservoirs as is seen in Ba- den, Germany (Scholz 2006a).

4.1.4.3 Drinking Water Supply

In the UK, there is an extensive network of current and former drinking water supply reservoirs, and these are a significant landscape feature in some areas. This reflects Scotland’s reliance on surface waters to supply drinking water. In many other parts of the world, groundwater is a significant source of drinking water, and therefore surface water reservoirs may be relatively rare. In Germany, for exam- ple, approx. 80% of drinking water is supplied by groundwater, while 70% of UK drinking water supplies come from surface waters (EU 2007).

4.1 Rapid Assessment Methodology for the Survey of Water Bodies 173

4.1.4.4 Production Industry

Many industries, from iron and steel production to chemicals to foodstuff manu- facturing, require high volumes of water to maintain industrial production. His- torically, many plants built their own water supply reservoirs, and in some cases these impoundments still exist many years after the industry they served has gone. It can be difficult to accurately identify such sites without reference to historic maps.

In the UK, the Ordnance Survey has made all their old maps available digitally, and these are a valuable source of information and freely available to researchers (via) the UK National Academic Data Centre (EDINA 2009). Industrial impound- ments can be found by comparing the series of historic maps for an area of inter- est. If similar high-quality map data are available for other countries, they should

be used as a definitive source of information. Regardless of how the information is obtained, any impoundments built for industrial use would receive a high percent- age for this category (Scholz and Sadowski 2009).

4.1.4.5 Sustainable Drainage

An SFRB may be a large SUDS, where the purpose is to uphold BMP in terms of infiltration, water quality improvement, and sustainable resource management (CIRIA 2004), which is the fundamental basis of current thinking on sustainabil- ity and seen as the BMP. New SFRB are designed to be sustainable (CIRIA 2004). However, this may not have been a consideration with historic SFRB, which were built before the modern practice of sustainability evolved. It is, how- ever, important to recognize that these older structures may now contribute to sustainable drainage either through hosting a wetland system or by providing retention capacity or, if silting up, by retaining sediments, which can be regarded as sustainable drainage, and a low value of between 0 and 20% can be assigned for older structures.

4.1.4.6 Environmental Protection

Some water bodies including SFRB may have environmental benefits and are even protected, because they are part of nature reserves or have received the designation Site of Specific Scientific Interest. These SFRB are mainly for the protection of animals, vegetation, and ecology. Normally, they will have signs indicating that there are protected species in the area or have warning signs indicating so.

In such cases the score assigned to environmental protection can be as high as 50%, with the other 50% of the bias and purpose assigned to drinking water sup- ply (Section 4.1.4.3) as was the original design purpose of the SFRB.

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4.1.4.7 Recreational Benefits

The main purpose of some water bodies may be to benefit the general public by providing recreational enjoyment including sports, walking, fishing, and bird watching. These SFRB can be easily identified as they are often managed; e.g., fishing areas are provided with huts, which provide fishing supplies and check permits of anglers.

4.1.4.8 Landscape Aesthetics

Most natural water bodies and some SFRB, often located in parks, contribute significantly to the aesthetic value of a landscape. These watercourses are looked after by a local authority to maintain an aesthetically pleasing view for walkers and other user groups.