Eutrophication of Tamar Lakes (1975–2003): a case study of land‐use impacts, potential solutions and fundamental issues for the Water Framework Directive

Abstract

Tamar Lakes is comprised of two reservoirs, which are located in South West England and in the headwaters of River Tamar at approximately 135 m above ordnance datum. Upper Tamar Lake (UTL) is a direct feed source reservoir of potable water in North Cornwall. Immediately following completion in 1975, UTL was subject to intense blue‐green algal blooms that continue to the present. These blooms create operational problems for water treatment, especially in hot‐dry years. Lower Tamar Lake (LTL) was constructed as a water supply reservoir in 1819 and became obsolete following UTL coming on‐line. Detailed water quality investigations over a period of some 28 years have confirmed the source of nutrient enrichment that fuels the algal blooms to be agriculturally derived, corresponding with a substantial increase in livestock farming. Associated poor land management practices, such as extensive field drainage and inappropriate slurry disposal to land, are linked with substantial elevations in organic contaminants such as ammonia, biochemical oxygen demand (BOD) and suspended solids (SS) during rainfall events. Evidence demonstrates that both reservoirs act as primary treatment lagoons, substantially reducing the worst of these pollutants and providing significant environmental gain. The implications of the Common Agricultural Policy (CAP), the Water Framework Directive (WFD) and regulatory monitoring are discussed in relation to resource management.

Assessment of salmon stocks and the use of management targets; a case study of the River Tamar, England

“…Within the Tamar catchment, the current estimate of usable area for salmon spawning and juvenile stages is 197 ha (Environment Agency 1997). There has been substantial water quality deterioration within the River Tamar over the past 30 years, particularly in the upper catchment north of Launceston (Hendry, Sambrook, Underwood, Waterfall & Williams 2006), although the overall water quality remains suitable to sustain populations of salmonids. The primary causes are land‐use changes and poor farming practice on agricultural land, the latter covering 92% of the Tamar catchment.…”

Bioavailable Nutrients (N and P) and Precipitation Patterns Drive Cyanobacterial Blooms in Missisquoi Bay, Lake Champlain

“…Conversely, a high number of small rainfall events could promote growth by continuously providing readily available nutrients [21][22][23]. While the impact of precipitation on the runoff of nutrients is well known and has been extensively modeled [24][25][26][27], the sequence of events from fertilizer application to precipitation and changes in N and P concentrations in water has not been well documented.…”

Comparison of Water Quality and Heavy Metals Concentration between Lata Janggut and Lata Keding, Jeli, Kelantan

“…In Malaysia, in addition to being used in producing agricultural products, aquatic inland reserves, Malaysia also serve as habitat for wildlife, including endemic and endangered species (Hendry et al, 2006). In addition, some efforts have been undertaken by the Department of Environment to maintain a reasonable standard of water quality despite the rapid urbanization of the reservoir catchment area.…”