Past projects - Drainage


The Halam Road site


Balancing pond during construction

Our initial involvement on this project was to report on the drainage aspects of a 5 acre green field site which was proposed for residential development. A previous planning application for the residential development of the site had been refused and subsequently dismissed at appeal and the drainage of the site was known to be an important issue.

A Flood Study of the catchment was carried out and the results of this study revealed that there were inadequacies with the receiving sewerage network which would be worsened by the proposed residential development. Our initial investigations identified three possible solutions to the drainage problems in this part of Southwell which comprised reinforcement of the existing sewerage system, the construction of an intercepting sewer to divert the catchment flows to the River Greet and the construction of a large balancing pond to regulate the catchment flows.

A preliminary design was then prepared for a balancing pond to serve the development, to reduce the rate of discharge from the proposed development site to its ‘green field’ level.

There was much local opposition to the proposed development, again with drainage being a major issue. After the production of our earlier reports and preliminary designs, parts of Southwell, adjacent to the site were subject to serious flooding.  Following the flooding, the capacity of the balancing pond was reassessed to determine if it could be increased to provide protection to the community against future flooding.  



ksa consulting engineers
consulting   civil  and  structural   engineers

Client:         Sir John Starkey
Location:     Nottinghamshire
 

 

 


 

 

 

Balancing pond 10 years after construction

The capacity of the pond was subsequently increased in order to take into account not only the flows from the proposed development site but also to regulate the flows from the upstream rural catchment.

The solution to the problems on this site involved the design and construction of a 5000 cubic metre balancing pond to regulate both the catchment and development flows. Approximately 500 cubic metres was required to balance the development flows and the total volume of 5000 cubic metres was needed to reduce the passing forward flows from the catchment as a whole, to a level of 100l/s. This value was set as being the maximum rate of flow the receiving sewerage system could accept without substantial reinforcement. In addition to the construction of the pond and the associated outfall structures, the scheme involved the construction of various intercepting sewers, to divert the existing flows into the balancing pond.

Land survey information was gathered digitally and construction drawings were produced on CAD for prior approval by the Local Planning Authority, Severn Trent Water Limited, the Environment Agency and Newark and Sherwood District Council. Approvals were granted in 1996 and a Contractor was appointed to carry out the construction work in early 1997.

The balancing bond is planned to be operational in 1997, not only bringing a real benefit to the local community but also allowing residential development to take place.

Following the successful implementation of the design, further projects are currently in progress in the Southwell area.

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