Portsmouth Water has been supplying water to Portsmouth and the surrounding area since 1857. The area supplied by the company extends through south-east Hampshire and West Sussex. Portsmouth Water owns around 55 sites from small covered reservoirs to larger reservoirs and lagoons. The company has a long history of good practice in consultation and development in an area with many important wildlife sites, and with landscape appreciated by residents and a large number of visitors. Many of these sites are of significant value for wildlife, encompassing chalk grasslands, Sites of Special Scientific Interest (SSSI), Sites of Importance for Nature Conservation (SINC), and Special Areas of Conservation (SAC). Where possible, Portsmouth Water's sites are managed for nature conservation within the operational constraints of the company.
In 2000 and 2001, ECOSA were commissioned to carry out ecology surveys of all Portsmouth Water sites. The surveys concentrated on establishing the habitat value of the sites, and identifying scarce, protected and Biodiversity Action Plan (BAP) species. Each site was evaluated based on the species and habitat types present and graded as being of low, medium or high conservation value, where high conservation value equates roughly to SINC quality.
In total six sites were identified as being of high value, 22 of medium value, and 27 sites of low value. From this ECOSA produced a Biodiversity Management Plan covering each of the medium and high value sites. This plan considered the habitats and species present and recommended appropriate conservation management for all of these sites.
In 2015 and 2016, ECOSA were again commissioned to update all the surveys on these sites and devise an updated Biodiversity Strategy for Portsmouth Water sites. Subsequently, further vegetation, bat and invertebrate surveys were carried out during 2016.