The Saltmarsh Project

Site location: Long Marsh – Totnes East Bank

Description: Long marsh is a small strip of semi-improved grassland and saltmarsh with limited hydrological connectivity to the estuary. The hard defences and raised banks of the 1830s subsequently disconnected the wetland from river, resulting in a transition to a more terrestrial habitat. In the upper reaches of the site, is mixed scrub and semi-improved grassland. Centrally, the area is dominated by Bolboschoenus maritimus swamp with rare occurrence of Scirpus tabernaemontani, Atriplex prostrata and other saltmarsh species. At the edges of the stream and on decaying wood, there are some species indicative of brackish conditions but the community is mainly Agrostis stolonifera subcommunity mixed with  mesotrophic grassland. These communities indicate that there is rare saline inundation. The stream appears to have a high level of suspended sediment, possibly due to the runoff from the catchment during periods of high rainfall. There is considerable path erosion from frequent footfall, maintenance of paths would likely strongly benefit the vegetation and reduce soil erosion.

Work Completed: > On site survey.

Work Planned: > Installation of an accessible boardwalk from the south end of the riverside footpath around the saltmarsh area.  This is a significant project that will be carried out in conjunction with South Hams District Council.

> Opening up of existing sluice to allow more frequent salt water inundation of marsh

> Leaky Dams upstream in stream, to help mitigate flooding and manage sediments

> Provision of improved site information.

Site location: near to 40ft Off red marker post – East Bank north of Sharpham North Quay.

Description: Opposite the buoy is a larger but heavily degraded stretch of marsh on the left bank. The intact sections of marsh holds a diverse short sward community, presumably grazed by geese. There are many standing pools containing a dense array of small invertebrate burrows. Large sections of the marsh have collapsed due to undercutting of edges and recent block collapse in places, but Bolboschoenus stands persist on some of the islands and lower sections which smooth out into mudflat areas. There is a large stand of Phragmites on the middle section of the marsh. The downstream sections have degraded into islands though none of degradation appears to be recent..

Work Completed: > On site survey.

> Installation of sedimentation monitor

> Installation of several hundred brushwood bundles to partially damn a number of the channels through the marsh, to encourage accumulation of sediment in the small channels.  This work was carried out by Dart Harbour & our contractor – Park Life, using low-impact manual methods.  Brushwood bundles were made from hazel and willow, locally coppiced and cleared from sites at Longmarsh, Sharpham and Ivybridge.

Work Planned: >LIDAR level survey

>Creation of small island of additional saltmarsh habitat downstream of existing marsh within the boundaries of the saltmarsh area using polders made of brushwood, as a test of concept for encouraging the restoration of a larger saltmarsh at The Gut site.

>Monitoring of impacts of brushwood partial damns on sediment levels.

>Surveys of fish

>Provision of information on the site

Site location: Fleet Mill Creek – East Bank behind Paddle Steamer Dam.

Description: Fleet Milly quarry is a an historic tidal creek of the estuary, blocked off with a seawall to become a freshwater lagoon but recently breached and presently reverting to its original tidal conditions,  bounded by a wall and a breached sluice. The Northern edge of the site is bordered by wet woodland, which according to the survey is in decline around the edges of the marsh, possibly due to saline intrusion. Bordering this wet woodland is a diverse reedbed with rare occurrence of brackish species, indicating a strong riparian (freshwater stream) influence with some saline intrusion. Below this zone, is a species-poor reedbed dominated by Phragmites, bordered with ditches and some raised banks home to Blackthorn scrub and Pendunculate Oak, some of which are dying back. Parts of this marsh are grazed by cattle.

A fringe of drier semi-natural woodland follows the edge of the marsh, which is potentially exposed to saline intrusion The reedbed smooths out into an intertidal mudflat habitat where Little Egrets have been seen foraging.  There is some loss of the southern bordering reedbed and willow scrub. On the southern side of the site, the mudflat rises up to a wall at which there is frequent occurrence of saltmarsh species such as Bolbschoenus maritimus, Triglochin maritima and Aster. Closer to the inlet channel, there is some occurrence of Spartina, Puccinellia and plenty of fucoid algae.

On the estuary side of the wall, lies a paddlesteamer, left there in 1923 and since colonised by a well establish saltmarsh community including Bolboschoenus maritimus and Spartina. The decay of the boat has resulted in some of the mud washing out, reducing the overall coverage. The recent die-off of vulnerable marsh has caused retreat and the expansion of bare ground.

Work Completed: > On site survey.

Work Planned: > Seed scattering using seed bombs of very locally collected seeds, to encourage development of appropriate saltmarsh species.

Site location: West shore of Stoke Gabriel Mill Pond

Description: At the upstream reaches of Stoke Gabriel, there is a small narrow strip of saltmarsh bordering the millpool. A footpath follows through this area of predominantly short sward marsh and across a small stream. There are patches of Bolbochoenus marsh and the foreshore is colonised by a small stand of Spartina. Along the edges of the stream are species associated with fresher conditions such as Wild Celery.

Due to heavy use of the footpath, and footfall making new routes through the marsh, there is considerable evidence of poaching, creating muddy areas, particularly around the boardwalks. This could easily be improved by maintenance of the path and boardwalks, and an informative plaque to encourage the public to appreciate the small, but diverse habitat from the path.

Work Completed: > On site survey.

Work Planned: > developing plans for a new boardwalk

Site location: East shore of Stoke Gabriel Creek

Description: Below the millpool weir is a small section of saltmarsh at the bottom of the South Downs Wood. This includes a shallow muddy to gravel bank and a large, steep bank of red gravel within which the marsh is nestled. A dense stand of Atriplex portulacoides sits at the edge of the gravel, and a small channel cuts through the mud of the saltmarsh, leading towards a longer strip of Spartina, and short sward Puccinellia marsh.
There is little evidence of damage from boat landing, though further erosion of the marsh from landing and footfall could be limited by improving path access leading to the gravel bank instead.

Work Completed: > On site survey.

Work Planned: > Installation of brushwood / coir / natural material barriers in the openings of larger channels, to facilitate accumulation of sediment in the channels