Policy information sourced from the Harlow Local Development Plan 2020-2033 PDF.
PL11: Water Quality, Water Management, Flooding, and Sustainable Drainage Systems.
1. Water Management
To minimise impact on the water environment, all new dwellings should achieve the Optional Technical Housing Standard for water efficiency of no more than 110 litres per person per day as described by Building Regulations.
2. Flooding
All development proposals will be considered against national policies (including application of the sequential test and, if necessary, the exception test) and against the European Water Framework Directive (or any subsequent equivalent).
Development must follow a risk-based and sequential approach, so that it is located in the lowest flood risk area. If this cannot be achieved, the exception test must be applied and the appropriate mitigation measures must be undertaken. Development must meet the following criteria:
- (a) it must not increase the risk of flooding elsewhere and must aim to reduce flood risk overall;
- (b) within sites at risk of flooding, the most vulnerable parts of the proposed development must be located in areas of lowest flood risk;
- (c) finished floor levels of development in Flood Zones 2 and 3 should be situated above the 1% (1 in 100 years) plus climate change predicted maximum water level, plus a minimum finished floor level of 300mm above the predicted water level;
- (d) proposed development in Flood Zone 3b must be ‘water compatible’ or ‘essential’ development;
- (e) development must be flood resilient and resistant, with safe access and escape routes, and it should also be demonstrated that residual risks can be safely managed;
- (f) any necessary flood protection or mitigation measures should not have an undue impact on nature conservation, landscape character, recreation or other important matters;
- (g) there should be no net loss in flood storage on-site;
- (h) flood flow routes should be configured to enable surface water to drain;
- (i) where necessary, planning permission will be conditional upon the submission and approval of a drainage management strategy that addresses all forms of flood risk.
Development within identified Critical Drainage Areas may, depending on the outcomes of a specific flood risk assessment, be required to contribute to funding for the delivery of appropriate flood alleviation schemes.
3. Waste Water and Sustainable Drainage Systems (SuDS)
Development proposals should identify how there is sufficient surface water, foul drainage and treatment capacity which can serve the development. Surface and foul water systems must be separate. The use of SuDS in all development proposals, including the retrofitting of SuDS, is encouraged and will be supported.
Where SuDS are required, the drainage scheme must meet the following criteria:
- (a) provide the most sustainable option from the SuDS hierarchy;
- (b) achieve multiple benefits including management of flood risk and surface water pollution, amenity and biodiversity;
- (c) achieve runoff rates in line with the guidance of the non-statutory technical standards for sustainable drainage;
- (d) provide appropriate attenuation taking into account climate change;
- (e) provide arrangements for future maintenance and management;
- (f) major proposals should also comply with the principles and standards set out by the Lead Local Flood Authority for SuDS.
4. Water Quality
Development must not cause deterioration to water quality, including quality of waterways and other bodies of water, identified Source Protection Zones (SPZ), Aquifers and all other groundwater. Development must aim to improve such water quality.
New development adjacent to water courses should seek to include restoration and deculverting. The culverting of water courses should be avoided. Where the applicant can demonstrate that deculverting or other river enhancements are unfeasible, a financial contribution will be sought to restore another section of the same watercourse.
New development adjacent to designated main rivers must provide and maintain an undeveloped buffer zone, of at least eight metres, to the watercourse. Such development must also include a long-term scheme to protect and enhance the conservation value of the watercourse.
For more information, please visit Harlow’s Local Plan here.