Dorset County, Borough & District Councils
Variability Along Sector / The Sector comprises two contrasting shorelines. The northern and eastern shores of Poole Harbour are largely dominated by man-made features and are highly urbanised. A developed shoreline thus exists from the east of Lytchett Bay to Sandbanks at the entrance to the Harbour. By contrast, the sheltered environment of the Harbour has allowed the development of wide tidal flats that grade landwards into extensive saltmarshes. A soft shore coastline of fine-grained sediments thus dominates the south and western shores of the Harbour from the western side of Lytchett Bay to South Haven Point.
Backshore Zone / The predominant shoreline type in the Harbour is the tidal mudflat with Backshore of saltmarshes. This shoreline type occurs extensively throughout the southern and western sections. High saltmarsh frequently occurs in a narrow strip between the upper Backshore and the extensive areas of lower saltmarsh of Spartina. The high saltmarsh is of mixed species. The Spartina in the lower saltmarsh is in natural dieback state.
The marsh system is low lying, with the lower saltmarsh being highly indented with creeks and muddy inlets. Large areas of natural heathland and sand dunes back these shores. The main sediment types present are soft muds, sandy muds and muddy sand. A second shoreline type occurs along the southern and western shores of the Harbour. This is a composite shoreline of sand and shingle Backshore with intertidal mudflats. Sand and shingle Backshore grading either into marshes or into heathland occur particularly around the Goathorn Peninsula and around the coast of Arne Heath to the west of Wareham Channel. Sand and shingle Backshore also occur around much of Brownsea Island and to the north and west of Furzey Island.
These sand and shingle Backshore form very narrow and steep beaches that possess a marked change in gradient to the very gentle slopes of the abutting tidal flats. Man-made Backshore dominates the northern and eastern shores. These are fringed in places with beaches comprised of mixtures of sand, shingle and mud. For example, beaches of mixed sediments occur between Lytchett Bay and Holes Bay and between Holes Bay and Sandbanks.
Intertidal Zone / The intertidal area of Poole Harbour occupies about 1980 hectares. Wide, flat mudflats that grade into saltmarshes above high water mark occupy much of this area. The intertidal area is characterised by fine grained sediment types, although there is a wide variety of sediment distributions in the intertidal zone. For example, intertidal flats of predominantly fine sand occur to the north and south of Brownsea Island, to the southwest and north of Furzey Island and off the Sandbanks area. Mud with some sand and gravel occurs in the flats in Arne Bay and in the eastern shore off Arne Heath. Muddy sand and sandy mud occurs over much of the intertidal area, as for example in Brand's Bay and Newton Bay, east and west of Furzey Island and in Holes Bay. The intertidal sediments are water-saturated and the mudflats have numerous small creeks, rills and channels that drain the mudflats at low tide.
COASTLINE DESCRIPTION - CONTINUED
Wave Energy / Wave action is slight in this low energy environment; the primary processes are a function of the tides.
Man-made features / Urbanised shores at Lytchett Bay to Sandbanks.
Boating marinas along the north and northeast coastal edge.
Piers/landing stages east of Lytchett Bay to Sandbanks, Brownsea and Furzey Islands.
Groynes at Sandbanks, and Brownsea Island.
Marine Biology: Littoral Zone Assessment / Poole Harbour is a large, sheltered marine inlet of biological significance, presenting a variety of environmental conditions and has a number of different habitats related to degree of shelter and sediment distributions within the Harbour. Four habitat types may be recognised:-
· very sheltered embayments with extensive saltmarshes;
· sheltered embayments lying closer to sea water channels;
· mudflats moderately exposed to wave action;
· Areas directly exposed to wave action.
Areas that are very sheltered from wave action generally possess soft muds, sandy muds and muddy sands. Examples of these areas include Newton Bay (SZ 004 856) and Brand's Bay (SZ 016 855). Areas that are more exposed to wave action, and, in particular, to tidal action tend to have sandier, more compact sediments with varying proportions of sand and gravel. Examples of such sites include the area to the west of Wych Channel (SY 985 876) and around Furzey Island (SZ 010 872).
Overall the Marine Biological Association has designated most of the Harbour (apart from an area west of Parkstone) as an area of Marine Biological Importance.
CONSERVATION
Sensitive Marine Areas / The mudflats support rich and diverse marine communities of plants and animals. There are large colonies of black-headed gull at Spartina Islands (SY 965 902), Round and Long Islands (SY 988 875) and Holes Bay (SZ 002 920). Other breeding birds include snipe and redshank. There are over wintering populations of dunlin, ruff and curlew and internationally important populations of black-tailed godwit and shelduck. Brownsea Island (SZ 020 880) supports breeding colonies of sandwich tern, common tern and gulls. There is a large heronry on Brownsea Island. Within Poole Bay there are offshore populations of wintering divers and mergansers. The subtidal shallow areas are of special interest to marine conservation and contain important muddy invertebrates and scour - loving sponges.
In addition to statutory designations Natural England has identified 3 important areas for marine wildlife (more commonly referred to as 'Sensitive Marine Areas' SMA’s) around Dorset. They are not designations but are used to indicate he presence of rich vulnerable marine species or habitats. The full descriptions of these SMA’s are in the SRC information file, All Dorset sectors are SMA’s.
RESOURCES AT RISK
Tourism and Recreation / Poole Harbour, although of considerable ecological importance, is also of major significance in terms of amenity and tourism. Coastal activities, especially boating and sport angling, are aspects of recreation most responsible for attracting visitors to the area. The development of the Harbour for water sports, casual recreation and access is encouraged as long as it does not conflict with sensitive areas of the Harbour. Sailing and boating in the Harbour is a major industry. The Harbour comes under the jurisdiction of the Poole Harbour Commissioners. The season for boating is from April to October, with the peak months being July and August. In the peak months as many as 8,000 boats may be moored in the Harbour area in marinas and on moorings. There are marinas at Sunseekers (Holes Bay), Poole Yacht Club (Hamworthy), Salterns, Cobbs Quay, Town Quay, Parkstone Yacht Club and Royal Motor at Sandbanks. There are approximately 4,000 swinging moorings throughout the northern half of the Harbour Dinghy sailing and racing areas are located in the north of the Harbour.Sport angling is very popular with several spots being well used. These include Poole Quay, Hamworthy, Salterns Pier, Sandbanks and South Haven Point. Boat fishing takes place in Wareham Channel, Middle Ground and Holes Bay.
Fisheries and Mariculture / Poole Harbour is also an important commercial fishing area. Trawling takes place in the Harbour, with the season running from about May to January. Prawns are netted in the Harbour in August and September, particularly around Furzey Island and grey mullet are fished in the area from late February to late November. The mudflats and channels in the Harbour are also exploited for eels, with the majority of catches being made from April to late October.
RESOURCES AT RISK - CONTINUED
Fisheries and Mariculture – Continued / Poole Harbour also supports significant intertidal fisheries for cockles, mussels, winkles, and clams and oyster breeding grounds, especially in South Deep Channel, with the latter being one of the most important oyster breeding grounds in Europe.
Industrial / See Fisheries & Mariculture
Water Abstractions - used for oil extraction at BP Wytch Farm
· Furzey Island - grid SZ 014872
· Cleaval Point - grid SZ 004861
Expected Claim Areas / Fisheries & Tourism
CLEAN-UP STRATEGY
Local Agreements
Special Consideration / Protection / Booming Positions
There are no limited booming positions in the Harbour. The velocity through the Harbour mouth does not make booming possible in this area.
Agreed Treatment (Natural England and Local Authorities) / No dispersants to be used without prior consultation with EN and MAFF.
Commercial Shellfish Layings - Consult with Southern Sea Fisheries District Committee before starting operations.
If oil does enter the Harbour booms could be used to divert the oil away from saltmarsh and mudflats.
Booms have been used for Newton Bay, Wytch Lake, and Furzey Island. Consultation with Southern Sea Fisheries Committee prior to starting operations.
Oil, which becomes stranded on the intertidal sand, should be removed using mechanical or manual methods of clean up.
Manual collection of tarballs and other oily debris.
Leave oil on the Spartina to weather naturally, dead plants may be removed by hand on the high tide line.
Equipment Guidelines / Held Locally:
· Poole Harbour Commissioners (PHC) hold a stock of first aid clean up equipment for small spills and their Harbour tug is available for agitation of sheen. PHC has an agreement with BP to provide Tier 2 resources.
Other Sources of Equipment:
· MCA Stockpile
· Weymouth Harbour Boom
Containment and Recovery / Many areas have been identified within Poole Harbour for local protection. In the event of oil entering Poole Harbour on a flood tide then the BP Exploration Oil Spill Contingency Plan: Dorset Operations should be consulted for containment and recovery operations (by courtesy of BP Exploration Operating Company Ltd).
Temporary Storage / Lined skips would be required for on-site storage of recovered oil or oily debris.
SENSITIVITY SCORE WORKSHEET: MANAGEMENT UNITS 1 TO 6
ECONOMIC / range / S / W / AESTHETIC / range / S / W
Income or Use Reduction / 0-4 / 3 / 3 / Scenic Quality / 0-4 / 4 / 4
Natural Resource Damage / 0-4 / 3 / 3 / Visual Impact / 0-4 / 4 / 4
Replacement / Restoration Costs / 0-4 / 3 / 3 / Local Appreciation / 0-4 / 4 / 4
Sub Total / 0-12 / 9 / 9 / Sub Total / 0-12 / 12 / 12
SOCIAL / range / S / W / ENVIRONMENTAL / range / S / W
Purpose of Use / 0-4 / 2 / 1 / Water quality Degradation / 0-4 / 4 / 4
Effect of Oil / 0-4 / 4 / 4 / Biological Productivity / 0-4 / 4 / 4
Degree of Direct Contact / 0-4 / 1 / 1 / Ecological Significance / 0-4 / 4 / 4
Amount of Use / 0-4 / 2 / 1 / Unique Habitat Uses / 0-4 / 2 / 3
Treatment before Use / 0-4 / 2 / 2 / Ecological Vulnerability / 0-4 / 4 / 4
Sub Total / 0-20 / 11 / 9 / Sub Total / 0-20 / 18 / 19
Total Sensitivity Rating / 0-64 / 50 / 49
AREA SENSITIVITY RANKING - The outside considerations listed below can be added to the total sensitivity rating to modify the score
OUTSIDE CONSIDERATIONS / range / S / W
Political Pressure / 0-4 / 4 / 4
Public Pressure / 0-4 / 4 / 4
Time Restrictions / 0-4 / 2 / 2
Sub Total / 12 / 10 / 10
TOTAL SENSITIVITY / 0-64 / 50 / 49
TOTAL MODIFIED SENSITIVITY / 0-76 / 60 / 59
SENSITIVITY SCORE WORKSHEET: MANAGEMENT UNITS 7 & 8
ECONOMIC / range / S / W / AESTHETIC / range / S / W
Income or Use Reduction / 0-4 / 4 / 2 / Scenic Quality / 0-4 / 2 / 2
Natural Resource Damage / 0-4 / 4 / 4 / Visual Impact / 0-4 / 2 / 2
Replacement / Restoration Costs / 0-4 / 2 / 2 / Local Appreciation / 0-4 / 4 / 4
Sub Total / 0-12 / 10 / 8 / Sub Total / 0-12 / 8 / 8
SOCIAL / range / S / W / ENVIRONMENTAL / range / S / W
Purpose of Use / 0-4 / 4 / 2 / Water quality Degradation / 0-4 / 4 / 4
Effect of Oil / 0-4 / 4 / 4 / Biological Productivity / 0-4 / 3 / 3
Degree of Direct Contact / 0-4 / 4 / 3 / Ecological Significance / 0-4 / 3 / 3
Amount of Use / 0-4 / 4 / 2 / Unique Habitat Uses / 0-4 / 3 / 3
Treatment before Use / 0-4 / 2 / 2 / Ecological Vulnerability / 0-4 / 3 / 3
Sub Total / 0-20 / 18 / 13 / Sub Total / 0-20 / 16 / 16
Total Sensitivity Rating / 0-64 / 52 / 45
AREA SENSITIVITY RANKING - The outside considerations listed below can be added to the total sensitivity rating to modify the score
OUTSIDE CONSIDERATIONS / range / S / W
Political Pressure / 0-4 / 4 / 4
Public Pressure / 0-4 / 4 / 4
Time Restrictions / 0-4 / 4 / 4
Sub Total / 12 / 12 / 12
TOTAL SENSITIVITY / 0-64 / 52 / 45
TOTAL MODIFIED SENSITIVITY / 0-76 / 64 / 57
SENSITIVITY SCORE WORKSHEET: MANAGEMENT UNITS 9 & 11
ECONOMIC / range / S / W / AESTHETIC / range / S / W
Income or Use Reduction / 0-4 / 2 / 2 / Scenic Quality / 0-4 / 2 / 2
Natural Resource Damage / 0-4 / 1 / 1 / Visual Impact / 0-4 / 2 / 2
Replacement / Restoration Costs / 0-4 / 1 / 1 / Local Appreciation / 0-4 / 4 / 4
Sub Total / 0-12 / 4 / 4 / Sub Total / 0-12 / 8 / 8
SOCIAL / range / S / W / ENVIRONMENTAL / range / S / W
Purpose of Use / 0-4 / 3 / 2 / Water quality Degradation / 0-4 / 4 / 4
Effect of Oil / 0-4 / 3 / 2 / Biological Productivity / 0-4 / 1 / 1
Degree of Direct Contact / 0-4 / 1 / 0 / Ecological Significance / 0-4 / 0 / 0
Amount of Use / 0-4 / 3 / 2 / Unique Habitat Uses / 0-4 / 0 / 0
Treatment before Use / 0-4 / 2 / 2 / Ecological Vulnerability / 0-4 / 0 / 0
Sub Total / 0-20 / 12 / 8 / Sub Total / 0-20 / 5 / 5