THE SUPPLY OF WETLAND ENHANCEMENT WORK AT RSPB BLACK DEVON WETLANDS

Tender description

Delivery of shallow excavation and earth moving work to deliver wetland habitat features at the RSPB Black Devon Wetlands reserve near Alloa. Lot 1: RSPB Scotland wishes to receive costings for each element of the work individually, as well as a total cost for the works. 1. Scrape Enlargement Adjacent to Boardwalk: Excavate areas of higher ground around boardwalk by approx. 1.3metres below its current level creating a water depth of approximately 30cm. Remove all willow trees within excavation footprint. Lower existing wetland around screen to similar height. Utilise soil to raise height of ‘island’ in adjacent wetlands above water level (see below). Area approx. 400 m2 2. Deepening of Existing Scrape Adjacent to Boardwalk: Excavate previously created scrape to increase depth by approximately 30cm to create a water depth of 0.3 to 0.5 metres. Area approx. 1000 m2 3. Western Scrape Creation: Top and lightly harrow area to the west of the main pool before creating several shallow scrapes (c approx. 30cm depth). Topping/harrowing area approx. 6000 m2. Scrape creation area approx. 700 m2 4. Re-instatement of Phragmites Channels: Re-Excavate previously created shallow channels through phragmites to remove re-growth and ensure channels remain open. Area approx. 800 m2. 5. Channel Excavation Around Seasonal Island: Excavate channel around existing seasonal island to a depth of approx. 0.5 metres. Area approx. 100 m2 6. Island creation: Utilising spoil from excavations create a series of low islands within main wetland pools. These islands should be no more than 0.3 metres above water level (same as existing peninsula) with shallow graded edges. Area approx. 200 m2. Any remaining spoil not utilised for island building should be removed to western edge of site. All measurements for the wetland features above are approximate and should be used as guidance only. We expect the successful contractor to work closely with the reserve team to finalise the finer details of the work while on site. It is important that spoil from the excavation is used to create low islands within the wetland or removed away from the wetland and placed in the spoil deposition areas outlined on the map. Please confirm that you are able to deliver this in your tender response. RSPB Black Devon Wetlands is a wet and marshy site and contractors will have to be comfortable working in these conditions. It is expected that the type of equipment and machinery used will be clearly stated in the tender and be suitable for the proposed work. This machinery should be suitable for deployment in wetland environments and spill kits maintained on site to contain any fuel or hydraulic fluids which may escape from machinery or storage tanks. Any storage tanks are required to be situated away from the working area and agreed in advance of site works commencing. In the interests of biosecurity, vehicles and equipment must be thoroughly cleaned before arriving on site and on departure. Finally, RSPB Black Devon Wetlands, and particularly the area around the viewing screen and footpath, is used by visitors. Safety of visitors and operators must be paramount and exclusion zones around working areas in proximity to visitor areas must be clearly demarked. Procedures must be in place to ensure work is stopped safely in the event of a visitor entering the working area.