Standing Open Water

Standing Open Water - John Miller - Explore Kent

Current Status

The Standing Open Water HAP includes lakes, meres and pools, as well as man-made waters such as reservoirs, canals, ponds, gravel pits and ditches with open water for at least the majority of the year. It includes the open water zone which may contain submerged, free-floating or floating-leaved vegetation, and water fringe vegetation. .This broad HAP has been derived to also include the UK BAP priority habitats 'eutrophic standing water', 'mesotrophic lakes', and 'aquifer-fed naturally fluctuating water bodies' Clearly there may be some overlap where standing open waters occur within larger BAP habitats such as grazing marsh, fens and reedbed. In such cases this plan should be seen as complimenting, and not superseding those wetland HAPs.

Standing waters provide habitat for a variety of threatened flora and fauna. Notable fauna include great crested newt (Triturus cristatus), water vole (Arvicola terrestris), medicinal leech (Hirudo medicinalis), and shining ramshorn snail (Segmentina nitida).

Kent supports a relatively large area of standing water, being rich in ponds (many of historic significance) and with particularly large areas of low-lying land drained by a network of dykes and ditches. Those on the North Kent, Sandwich, and Walland Marshes support important invertebrate fauna and are of international importance.

Lakes are concentrated along the river valleys of the Darent, Medway, Stour and at Dungeness, mainly as a legacy of mineral exploitation. Reservoirs are mostly small farm reservoirs, but include small water company resources plus the two main ones at Bewl and Bough Beech. There are two canals; the Royal Military Canal and the Thames and Medway Canal at Higham. Ponds occur throughout Kent, but are very characteristic of the Central Low Weald and the High Weald.

Factors

  • Climate change: A substantial change in water supply and through-put would alter the character of water bodies and a rise in temperature would produce wide-ranging effects such as acceleration of plant growth.
  • Pollutants: Organic and inorganic fertilisers cause nutrient enrichment (eutrophication) of the water, damaging plant and animal communities. Diffuse-source pollution generally exceeds that from point-sources.
  • Changes in land cover, such as the loss of waterside vegetation, can lead to the release of unwelcome nutrients and silt into water bodies, causing enrichment and smothering fish spawning sites and aquatic vegetation.
  • In-filling of ponds and ditches, leading to loss of open water habitat. This is a major factor in the decline of species such as great crested newt.
  • Water abstraction for potable supply, industry or irrigation - from standing water bodies,surface feeders and aquifers - can depress water levels and reduce throughputs of water. Low water levels cause shallow lakes to dry out; marginal vegetation to deteriorate; and nutrient enrichment to increase.
  • The introduction and manipulation of fish stocks for angling, and removal of predators, leads to the loss of natural fish populations and plant and invertebrate communities.
  • Recreational activity on standing open water impacts on the natural habitat. The disturbance can affect bird populations; trampling can degrade marginal vegetation; and boat hulls and propellers can destroy aquatic plants and stir up sediment, contributing to eutrophication. The construction of marinas and other leisure facilities may also destroy valuable habitat and lead to increased pollution.
  • Release of non-native plants and animals can be very damaging. For example, the non-native signal crayfish, Pacifastacus leniusculus, has spread crayfish plague which has eliminated many populations of native crayfish, Austropotamobius pallipes.

Current Action

  • The European Water Framework Directive, when implemented, will identify those waterbodies over 5ha in size, or in Natura 2000 Sites, failing to achieve 'good ecological status (or potential)' and remedial action will be required by statutory agencies.
  • DEFRA's Countryside Stewardship Scheme has been funding pond restoration and creation projects since 1991. The new schemes that were launched in March this year, Entry Level Stewardship (ELS) and Higher Level Stewardship (HLS), also have options for ponds and scrapes.
  • Countryside Management Partnerships (CMPs) in Kent co-ordinate volunteer support to help landowners create their own wildlife-friendly ponds.
  • Advice on pond management is available via the BTCV Pond Wardening Scheme, the High Weald and North Downs AONB Units, and from CMPs (e.g. the Stour Valley Pond Project). Small grants are also sometimes available from such bodies.
  • Gardening for Wildlife initiatives across Kent promote the creation of wildlife-friendly ponds in your back garden (e.g. those led by KWT, EN, RSPB, supported and promoted by local planning authorities)
  • Public bodies, water companies and NGOs positively manage standing open water within their landholdings.
  • Many standing waters form part of nationally or internationally designated sites such as at Stodmarsh.

Objectives

  1. Maintain the condition of open waters currently judged as in favourable condition within important sites/landscapes (SSSI, SNCI, AONB). Maintain the condition of all other high-quality sites where feasible.
  2. Initiate action to restore to favourable condition (typical plant and animal communities present) sites that have been damaged or neglected, particularly within important sites and landscapes.
  3. Increase the abundance of standing open water habitats where appropriate, particularly wildlife-friendly ponds.

Relevant Habitat Action Plans

The relevant UK Habitat Action Plans:

The relevant UK Species Action Plans:

The relevant Kent Habitat Action Plans:

  • Saline lagoons