Environment Agency 1997 Local Environment Agency Plan, West Dorset, Consultation Draft Nov. 1997.

Action plan (post consultation) due to be published summer 1998.

Average annual rainfall for the coastal area surrounding the Fleet is 701-750mm, rising to 800mm in the higher ground from which the tributaries which feed the Fleet at Abbotsbury and Roddon Hive originate. There is a tidal level monitoring station and current daily raingauge at Portland, and another daily raingauge at Weymouth just north of The Narrows.

The three streams which flow into the Fleet are all classed as RE1 (River Ecosystem Class 1- Water of very good quality suitable for all fish species).

ARivers, ponds and the ... Fleet and Portland Harbour may be suffering from diffuse inputs of nutrients and pesticides which are threatening the wildlife resource of the area. The water quality of the Fleet is being monitored quarterly; possible factors include agricultural activities and swan fouling.

EA will encourage landowners to establish buffer zones between intensive farmland and watercourses wherever possible.

The Fleet lagoon has priority status (under the EC Habitats Directive Regulations) Aand there is evidence that its botanical interest is declining. We should work to establish the causes, develop plans to improve the habitat diversity of the hinterland, seek to restore ditch systems, establish sustainable inputs of nutrients and set target levels, and monitor the status of the chemistry and the animals and plants. AThere is potential for restoration and enhancement of the river corridor, particularly to improve ... streams flowing into the Fleet, by restoring natural channel shape and reinstating meanders and side ditches. EA are working with the developers of Portland Harbour (Portland Ports Ltd) to ensure their operations can be carried out without detrimental impact on the sensitive habitats contained within the harbour itself and in the internationally protected lagoon of the Fleet whose only connection to the open sea is through the harbour. EA are undertaking quarterly surveys to ascertain any water quality impacts as a result of the redevelopment of Portland Harbour into a commercial port receiving fertilisers and molasses, and other commercial activities. Boat surveys will be undertaken in 1997 after which further monitoring will be reviewed.

The catchment of the Fleet is a narrow strip of undulating arable or improved pasture running northwest from Weymouth to the Abbotsbury swannery, backed by the steep slopes of White Hill and Portesham Hill. Fences or stone walls are more a feature of this open landscape than the hedges in the catchments to the west, and there are few trees or copses. The three short streams (Rodden, Portesham Mill stream, Cowards Lake) flowing into the Fleet have modified channels for much of their length and a number of the old ditches have been lost.

Two sites within Portland Harbour are monitored under the EC shellfish waters Directive (79/923/EEC) to protect shellfish waters from pollution. In 1996 the standards for copper and zinc were exceeded. A study is underway to identify any sources and long term trends in water quality or bioaccumulation in shellfish tissue. The EC shellfish hygiene Directive (91/492/EEC) defines standards for shellfish quality required in the end product, and classifies shellfish harvesting areas into 4 categories according to the concentration of bacteria found in the shellfish flesh. A site in the Fleet, and one within Portland Harbour have been classified within the area. In 1996 both achieved a B classification, a deterioration from an A classification in 1995.

Two Wessex Water Services consented STW discharges exist to tributaries of the Fleet, at Abbotsbury (DWF 101-1000 m3/day) and at Langton Herring (no consented DWF, max. daily flow only). A further four private sewage treatment works with consented maximum discharge volume of >5 m3/day discharge to the Fleet at Abbotsbury (<10 m3/day), Langton Hive (26-50 m3/day), Chickerell (>50 m3/day) and the west end of the Narrows (<10 m3/day).

The enclosed waters of Portland harbour are of high scientific interest for their marine communities and rare species with a southern distribution, such as an anemone (Scolanthus callimorphus), a rare sea slug (Aeolidiella alderi) and an ascidian (Phallusia mammillata). The rich sediment communities are considered to be of national importance and include the extensive eelgrass beds (Zostera spp) and mud plains dominated by the fragile sea pen (Virgularia mirabilis) and a Mediterranean polychaete (Sternaspis scutata). With the departure of the Navy, careful planning is essential to balance the development of industry and recreation with the needs of the precious marine biota. The consequences of a diesel spill or substantial pollution from a refuelling factory ship would be severe. The Fleet is the largest saline lagoon in England and a candidate SAC. Poor flushing leaves a fine substratum with good stands of all three eelgrasses (Zostera spp), both tasselweeds (Ruppia spp.) and a rare stonewort (Lamprothamnium papulosum). There are tidal rapids with rich sponge communities and many rare species within the lagoon; the lagoon sand worm (Armandia cirrhosa), de Folin=s lagoon snail (Caecum armoricum), the starlet anemone (Nematostella vectensis), the gastropod (Paludinella littorina) and the lagoon sea slug (Tenella adspersa) are nationally rare and protected. The Fleet is a site of national importance for wildfowl and wetland birds. Redshank, as a breeding species, are almost restricted to the areas around the Fleet and Portland Harbour. The ringed plover, oyster catcher and little tern are similarly restricted in distribution. The Abbotsbury swannery is famous and with the gardens, is a major visitor attraction. The swan herd is believed to be increasing, resulting in excess nutrients entering the Fleet and overgrazing of the seagrass. There has been a decline in the botanical interest and algal blooms implying eutrophication but this has not been verified by a survey. Other potential threats are from silt, shellfish farming and Japanese seaweed (Sargassum muticum). The Chesil Beach is an exceptional geological feature and it supports extensive shingle habitats with rare plants such as the sea pea (Lathyrus japonicus) and breeding little terns. It is the only British site for two invertebrates, the scaly cricket (Megoplistes squamiger) and the darkling beetle (Omophlus rufitarsus). Babington's leek (Allium babingtonii) grows in substantial colonies at Abbotsbury.

The Fleet is a designated bass nursery area (SI 1156 1990) and fishing from boats is prohibited at all times. This prohibition does not apply to the shore and there is one fisherman using a tidal net for bass in this area, which is not abiding by the spirit of the designation. There is also a prawn fishery off the old Ferrybridge, known locally as the Billy Winter fishery. The private fish farm within the Fleet is not governed by the Sea Fisheries Committee restrictions. The EA issues eight licences (for 10 fyke nets each) annually for eel fishing on the Fleet. Reported annual catch varies from a minimum of <500 kg to over 2500 kg.

There is one groundwater abstraction licence for public water supply within the Fleet catchment, at Portesham on the upper Abbotsbury tributaries, of between 0.5 and 5.0 Mld.

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