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Full SuDS Adoption Policy

1 Purpose

Essex County Council (ECC) has a dual function as both a Lead Local Flood Authority (LLFA) and a Highways Authority (HA) in relation to drainage from new developments. The LLFA is responsible for managing risks of flooding from surface water, groundwater and ordinary watercourses including as a statutory consultee to planning applications. The HA must adopt associated drainage from highways and manage risks of flooding to the highway.

In order to align the two areas’ approaches and provide clarity for developers, this policy has been developed to outline when we would consider adoption of SuDS.

2 Introduction

SuDS are required to be provided on new developments by the National Planning Policy Framework and many Local Plan Policies. From the 15th April 2015 the LLFA is a statutory consultee to the planning process and will advise whether or not there are appropriate surface water drainage arrangements in place.

Applications for planning permission must outline who will be adopting the drainage system and set out a maintenance regime with the minimum requirements for maintenance. The LLFA must advise whether the maintenance arrangements are economically proportionate.

It is in the LLFAs and the HAs interest to use the opportunities offered by development to reduce the risks of flooding. It is not always appropriate for new developments to just look to mimic the existing situation, as required by the Non-Statutory Technical Standards for SuDS which the LLFA must look for developments to accord with, if there is an existing flooding problem or high risk in that area.

As there is no duty for ECC to adopt SuDS that take highway and private water, we have outlined in this document our exceptions policy where, in order to negotiate improvement works as part of new developments, the Council has agreed to adopt SuDS in certain situations and subject to appropriate agreement, fees, approval and commuted sums.

3 Policy

ECC has a policy of not adopting SuDS unless exceptional circumstances prevail. The developer must be able to demonstrate that it is not possible for the SuDS to be adopted by a water company, with design changes if necessary.

Where either

(a) there are known existing highway and/or property flooding problems; or

(b) there is a flood investigation report for the area, the site is in or adjacent to a critical drainage area (defined in Surface Water Management Plans) or there are significant areas shown to be at risk on the updated Flood Maps for Surface Water and the developer has incorporated alleviation measures within their site to significantly improve the risk, ECC will normally consider this to constitute exceptional circumstances.

What will constitute a significant improvement will depend on the context but it will need to lead to a reduction in the likelihood and severity of any flooding so as to justify the adoption of maintenance liability for the SuDS.

4 Process

The process by which developers must obtain approval from ECC to adopt are as follows:

1. SuDS Adoption Policy which you are currently reading.

2. Developer to consider whether another organisation can adopt the SuDS.

3. Developer will enter into discussions with Flood team as to whether their SuDS has a wider function which meets the criteria for adoption. The Council’s Director of Highways or Director of Environment & Economy will make the decision following discussion with the Flooding Team on adoption cases. Where there are borderline or controversial cases, this discussion will include the relevant Cabinet Member who may then wish to make the decision in some cases. The Flood team will then advise the developer whether or not the Council wishes to consider the SuDS on the development for adoption and whether the developer may proceed with a SuDS application if they so wish.

4. Assuming the criteria are met, developer to submit a SuDS application and appropriate fee payable to LLFA for review of all relevant information (this would be over and above statutory duty as it will take extra time to ensure details are acceptable to allow adoption).

5. The LLFA will make clear in writing within 28 working days whether the system is acceptable to ECC for adoption.

If the SuDS drains a highway and can be reasonably incorporated into the highway:

6a. The SuDS will be adopted as part of the highway under Section 38 of the Highways Act 1980. The Developer will be required to pay the Council’s fees associated with the approval of the design and supervision of the works along with a commuted sum for ongoing maintenance. Or, if there are non-highway SuDS or SuDS which cannot reasonably be incorporated into the highway:

6b. The Council will consider adoption by land transfer to this Council as either a freehold or long leasehold. Even if other criteria are met, the Council will not acquire any interest in land where it considers that this will expose it to onerous risks or liability as the occupier of land. The developer will be required to pay the Council’s fees associated with the approval of the design and supervision of the works along with a commuted sum for ongoing maintenance. The Developer will also be required to pay the Council’s legal and surveyors costs associated with the land transfer along with any taxation liability associated with the transfer.

7. Once adoption has been agreed in principle and the SuDS has been inspected and signed off by the Council as being built in accordance with approved drawings this Council will adopt on the expiry of one year, provided that the developer has satisfactorily maintained the SuDS during that period.

5 Fees

The fees applicable at stage 4 of the process are as follows:

SuDS applications sent to the LLFA for approval

  • Up to minor (1-9 dwellings) £478
  • Major (10-199 units, 0.5-3.99 ha site area or 1000-9999 sq.m floorspace) £858
  • Large-major (200+ units/over 4 ha site area or over 10,000 sq.m floorspace) £1824

The fees are set at a level to allow cost-recovery and will be reviewed at the end of the financial year to ensure that, taking one year with another, they do not exceed the cost to the authority of carrying out the work.

The fees applicable at stage 6a above would be the current fee charged by Development Management of 8% of the total construction cost of adopted works to cover technical approval, managing the agreement and an inspection fee.

The fees mentioned at stage 6b above will be communicated to the Developer as early in the process as possible so that they are able to decide whether to proceed.

Commuted sums will be charged for adoption of non-standard features including SuDS since there is a recognised short term increase in maintenance costs. The fees will cover 30 years due to the longer life span of SuDS as opposed to conventional drainage.

6 Key principles and design standards

Developers are not required to ask ECC to adopt any SuDS. ECC will only adopt SuDS if the criteria in this policy are met. Through the planning process, the developer must meet the requirements of the local planning authority relating to the demonstration that there will be an appropriate adopter and agreed maintenance regime outlining the minimum standards for maintenance of the system in place. This adoption option will aid in meeting this requirement for developments meeting the exceptions.

The key principles relating to any adoption are:

  • The sustainable drainage system is comprehensive, well designed and is of a good standard that this Council has approved;
  • An agreed commuted payment is secured which meets the cost of managing and maintaining the asset;
  • The drainage systems are capable and designed to receive highway and non-highway water;
  • The drainage systems are only in new developments where the Council as the adopting authority has had opportunity to approve and inspect drainage design (and therefore we would not include any retrospective adoption).

The design criteria which the LLFA will refer to prior to approving the scheme for adoption are:

  • The non-statutory technical standards for sustainable drainage systems, which set out the minimum requirements;
  • The ECC SuDS Design Guide, which sets out our additional local requirements
  • The CIRIA SuDS Manual (CC697);
  • BS8582 Code of practice for surface water management for development sites.
    The LLFA will consult with Development Management to ensure the design is compliant with Highway Policy.

7 Extent of Drainage Adoption

The drainage system to be adopted may consist of an extent of piped network, soakaways, underground attenuation systems, permeable pavements, filtration trenches, swales or other vegetated sustainable drainage elements, designed to manage surface water flows from both roof and highway areas, provided it complies with standards as specified by ECC.

Elements situated within the boundary of dwellings or other occupied properties will not be adopted.

8 Specific adoption requirements

Below grade attenuation: Below grade attenuation shall only be adopted if appropriate cover is provided with a downstream and upstream inspection chamber and the attenuation system is located within a non-trafficked area within the highway verge or open space.

Ponds and wetlands: Adoption will occur up to the outfall headwall to the pond or wetland. The pond or wetland area will not be adopted by ECC. The Developer may consider asking the district or parish council to adopt this area if it is within an area which is or which will become public open space. ECC will consider adoption of any communicating pipe work from the pond/wetland outflow to the sewerage undertakers’ demarcation chamber or final outfall upon site specific consideration.

Drainage elements proposed for adoption which utilise infiltration will normally only be adopted if infiltration is greater than 1x10-5m/s, demonstrated through appropriate ground investigation.

9 Other Highway requirements

The developer must comply with any other requirement of the local highway authority for the adoption of highways.

The local highway authority may require the payment of commuted sums for the adoption of any drainage feature.

10 Available data

Data currently available to ECC in respect of known high risk or known flooding areas can be found:

  • In individual Surface Water Management Plans;
  • On the Flood Incidents layer held by the Flood and Water Management Team;
  • On the updated Flood Maps for Surface Water held by the Environment Agency.
  • Information relating to these can be requested via the Flooding pages of the ECC website.

Request information held by Essex Highways in relation to highway flooding incidents.