Improve water quality
In the words of Hertfordshire Environmental Forum’s “50-year vision for the wildlife and natural habitats of Hertfordshire”:
“Water quality deteriorates with increasing urbanisation as surface run-off carries with it increasing loads of pollutants and sediments. Rain falling onto towns has the beneficial effect of washing away much of the accumulated dirt from the previous dry period. However, the result is that stormwater may contain a wide variety of pollutants including suspended solids, nutrients (nitrogen and phosphorus), toxins (including heavy metals and pesticides), pathogenic microorganisms (bacteria, viruses and others), oil, detergents and de-icing chemicals. The problem of pollution by sewage and industrial wastes is not confined to urban areas. However they more often have their origins in urban areas and so the effects are most concentrated there.”
Effective development drainage strategies as part of an Integrated Water Management strategy to mitigate overflow following heavy rainfall will help to prevent unmanaged surface water contamination.