Environmental Engineering Reference
In-Depth Information
has involved the collaboration of experts in various hydrological and ecological ields. Judgments are
made about the ecological consequences of various quantities and timings of low in a river by using a
mixture of existing and newly acquired data (Acreman et al. 2003).
4.6.2.4.2 European Water Framework Directive and CAMS
The CAMS was developed by the Environmental Agency (Environment Agency 2010) of England
and Wales following the government's decision to apply more control on how much water is taken
from rivers, reservoirs, lakes, and other waterbodies. The CAMS was developed based on the
European Water Framework Directive (WFD), which was implemented into U.K. legislation in
2003. The WFD created new requirements for the protection of water resources and requires that
water resources management is carried out in an integrated way.
For surface waters, the WFD requires that the impact of pressures is measured against natural
low conditions, where natural low is deined as the low that would occur if all artiicial inluences
(abstractions, discharges, low regulation) were not taking place. Surface waters are assessed as
having high, good, moderate, poor, or bad ecological status. High ecological status (HES) water-
bodies are those essentially undisturbed and must be maintained at that condition (not be allowed to
deteriorate). The WFD requires that all surface waterbodies be at good ecological status (GES) by
2015, unless an alternative objective can be justiied, where a GES basically means that lows must
remain above the lows required by the biology. Figure 4.32 illustrates how the ecological status is
determined in relation to the natural low condition.
Groundwaters may be classed as either good or poor based on their chemical status and ground-
water abstraction pressures and the WFD requires that all groundwater bodies achieve good status
by 2015 unless alternative objectives are justiied.
The CAMS process is a legal framework for the implementation of the WFD, which includes
measures to control abstraction pressures and promote eficient and sustainable water use. The pro-
cess is illustrated in Figure 4.33.
The CAMS process includes the participation of interested parties through a catchment stake-
holder group and a resource assessment and management (RAM) framework (Acreman et al. 2003).
The CAMS process (Figure 4.34) includes:
Building block approach
60,000
50,000
Overbank flow recommendation
40,000
High flow pulse recommendation
30,000
Subsistence flow
recommendation
Base flow recommendation
20,000
10,000
0
Oct.
Nov.
Dec.
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
FIGURE 4.32
An example of an integrated hydrograph based on the building blocks of subsistence, base,
high-low pulses, and overbank lows. (From NRC, The science of instream lows: A review of the Texas
instream low program, Committee on Review of Methods for Establishing Instream Flows for Texas Rivers,
National Research Council, The National Academies Press, Washington, DC, 2005. With permission.)
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