Agenda item

Sewerage Infrastructure and Discharge within Rushcliffe

Report of the Director – Neighbourhoods



The Chairman reminded the Group that the Scrutiny Matrix submitted specified that Councillors wanted to understand the situation in Rushcliffe regarding the sewage infrastructure and any unlawful discharges.


Richard Cooper, Sustainable Places Team Leader at the Environment Agency delivered a presentation outlining planning and wastewater from the perspective of the Environment Agency.


Mr Cooper advised the Group that in respect of strategic planning the Environment Agency would normally provide comment on documents that form part of a local plan, including Water Cycle Strategy, Strategic Flood risk Assessments, Surface Water Management Plans, Strategic Infrastructure Plans, Environmental or Green Infrastructure Study, Strategic Housing and Employment Land Availability Assessments as well as main planning documents (Local Plans). Mr Cooper advised that in most cases such comments would be in the line of:


·       All development should connect to the existing foul drainage network

·       Development will need to ensure there’s available capacity within;

a)    The receiving sewerage network; and

b)    The sewage treatment works

·       Developers and the Local Planning Authority should confirm available capacity with the water company prior to allocating sites

·       Development and Growth should not impact on the quality of watercourses in the Borough


It was noted that in respect of developmental planning the Environment agency would respond to a major development (10 or more dwellings) or where a proposal is not to connect to mains drainage.


Mr Cooper provided the drainage hierarchy as follows:


1.     Infiltration to ground

2.     Discharge to surface waterbody

3.     Discharge to surface water sewer/highway drain or other

4.     To a combined sewer


The group were provided with an explanation of how the sewerage system works, from wastewater (foul) being flushed away from properties, flowing to a local wastewater treatment works (WWTW), to then arriving for treatment before being discharged back into the watercourse. It was noted that in older systems both foul and surface water use the same pipe (combined system) and newer systems have separate pipes. However, whilst new housing schemes will have separate systems, it does not mean the system further downstream is separate.


In respect of rainwater some WWTW have storm tanks that provide storage when the incoming flow is greater than the capacity to treat. However, if the storm tanks are full, then to prevent the treatment works being flooded or the foul water backing up, the wastewater is allowed to spill. If pumping stations fail or breakdown then these too are allowed to spill. It was noted that such spills are monitored by the Government.


Mr Cooper explained that the Environment Agency administrates and regulates wastewater spills under the Environmental Permitting Regulations, adding that there is no limit on how often a storm overflow operates providing it is compliant with the permit. It was noted that the WWTW at Cotgrave has closed with the Radcliffe on Trent WWTW now receiving their sewage, adding that discharges are made directly into the River Trent. Mr Cooper advised that the WWTW at Radcliffe on Trent does have limits on when it should overflow but not on frequency and these occurrences are monitored.


Mr Cooper added that when a Combined Sewer Overflow spills above the Storm Overflow assessment Framework threshold this will be investigated by Severn Trent Water including the Combined Sewer Overflow at Radcliffe on Trent. It was noted that Severn Trent Water has a good performance on discharge permit compliance. In addition, the new Environment Act 2021 has introduced a Storm Overflow Reduction Plan that will drive further improvement to reduce the number of spill events and the focus for the Environment Agency is to make sure everything that should be treated is treated and that sewage flows are not by-passing a storm overflow.


Chris Bramley, Strategic Catchment Planning for Severn Trent provided the Group with an overview of how Severn Trent identifies and understands the risks associated with development and what is being done to accommodate growth within Rushcliffe.


Mr Bramley informed the Group that developers have the right to connect to the sewerage system and as a water authority, Severn Trent is not able to refuse connection due to lack of capacity. Mr Bramley explained that Severn Trent engages with the Local Planning Authority at various stages of the Local Plan development process and that planning applications are reviewed by their Networks solutions department and where assessments indicate a risk these would be reviewed by the Asset Protection Department before advising on what conditions may be required or where schemes to provide capacity for growth are needed. It was noted that new schemes are assessed on a priority basis across the Severn Trent Region and are funded through the Community Infrastructure Levy charges (CIL).


Mr Bramley advised that Severn Trent operates a 5 Gate process in respect of promoting and delivering schemes:


·       Gate 1 - High level assessment of risk to ensure that investment is allocated to the most appropriate locations

·       Gate 2 - Project feasibility, where a more detailed understanding of the risks and the concept solutions are developed – this stage involves surveys, flow analysis, costs and benefits of the scheme

·       Gate 3 - detailed design phase, where final solution is developed

·       Gate 4 - Delivery stage during which the scheme is completed

·       Gate 5 - Scheme review where the project delivered meets its set objectives

Mr Bramley provided an illustration of Rushcliffe’s Local Plan sites and some additional sites and the stage in the above process each is at.


Mr Bramley continued his presentation advising the Group of Severn Trent’s draft Drainage and Wastewater Management Plan, which sets out how the water authority will extend and maintain a robust and resilient drainage and wastewater system. Mr Bramley explained the Plan provides greater transparency of current and future risks and consistency across the water industry with emphasis on wastewater and working collaboratively with stakeholders to mitigate future pressures associated with climate change, population growth and urbanisation.


Mr Bramley provided a timeline of objectives over the next few years including:


·       Protection of river quality - by reducing storm overflow spills and upgrading storm overflows, in order that none of the drainage operations cause Reasons for Not Achieving Good Status (RNAGs) for rivers.


·       Make areas more flood resilient – by upgrading surface water drainage, including improved engineering methods to separate surface water and nature-based solutions.


·       Improve Capacity of our Wastewater treatment – by upgrading wastewater treatment works and processes to improve capacity


The Group noted that the consultation period for the Drainage and Wastewater Management Plan runs until 30 September 2022, with the final plan due to be published in December 2022.


Councillors commented on the Local Plan and Rushcliffe having a 30% increase in population due to housing development and reported issues in respect of flooding and sewerage spills at East Leake and Sutton Bonington. Councillors asked whether more robust planning conditions would help alleviate and prevent spills in future.


Councillors also commented on the closure of the WWTW at Cotgrave and whether the WWTW at Radcliffe is able to cope with the extra capacity.


Mr Bramley explained that there has been some investigation work at Sutton Bonington and at East Leake where issues were not picked up due to windfall developments, Mr Bramley advised that a new scheme was coming forward at Kingston Brooke which will alleviate some of the issues at East Leake.


Mr Cooper informed the Group that new developments are treated appropriately in respect of planning and planning conditions and reminded Councillors that Severn Trent cannot refuse connection to the water system for any new developments, and explained that attenuation areas and tanks are robust enough for most new developments. Mr Cooper added that both Severn Trent and the Environment Agency have set rules to follow and suggested that local authorities can influence what is agreed at the Strategic Local Plan stage.


Councillors raised concerns in respect of surface water flooding and the water authority and Environment Agency relationships with the local flood authority. Councillors also commented on where combined sewers were located and whether residents have access to such information. Mr Bramley advised that regular liaison meetings do take place and planning is often discussed, in respect of improvements and budget streams the Draft Wastewater Management Plan once adopted, would assist with long term schemes coming forward and allow for extra growth in the system. With regard to information on combined sewers, Mr cooper advised that it is difficult to provide data that can be easily accessed as there are a number of organisations involved. Councillors noted this highlighted a problem in respect of public access to information and being able to report areas of concern and flood occurrences.


Councillors asked Mr Cooper from an environment view, how effective were the permits and conditions issued to Severn Trent and how are environmental breaches monitored and reported. Mr Cooper explained that monitoring is taking place within a wider framework directive and that there is an element of self-regulation for water authorities within the parameters of their permits. It was noted that Severn Trent report breaches to the Environment Agency.


With regards to funding streams for additional improvements to the system the Chairman asked whether Severn Trent can request funding contributions from the developer. Mr Bramley explained that the Community Infrastructure Levy (CIL) is charged to the developer, it is then up to the local authority how the CIL money is spent.


The Chairman suggested that this item be brought back to a future meeting of Growth and development scrutiny and that in the meantime the Council would improve its relationships with agencies to mitigate the impact of flooding events.


It was RESOLVED that the Growth and Development Scrutiny Group:


a)    Considered the key lines of enquiry contained in the scrutiny matrix and asked questions of the expert speakers


b)    Requested that further scrutiny, related to sewerage infrastructure and discharge be brought back to a future meeting of this committee.


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