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Title: Hysim model : modelling the flows of the River Deben
Author: Andy Turner
Document Type: Monograph
The need to refine the environmental flow requirement of the River Deben was highlighted in the Deben Groundwater Unit Water Resources Management Plan. This had previously been identified by Southern Science2 as 0.076 cumecs (6.57 Ml/d) based on the velocity and level requirements of key indicator species at three representative locations upstream of the reaches suffering from low flows during dry periods. However, as part of the naturalisation process, spray irrigation abstractions had been distributed evenly over a six month period and groundwater abstractions had not been taken into account at all. The Quality Review Panel of the Southern Science work, recommended that refinements were made to the allocation. Interim refinements, using monthly abstraction returns for spray irrigation resulted in a reassessed value of 0.088 cumecs (7.6 Ml/d). This modelling work takes account of the groundwater abstraction in the catchment, and arrives at a minimum environmental allocation of 0.084 cumecs (7.1 Ml/d). This value is equivalent to the 98th percentile of natural flow at Naunton Hall. It is considered that this is the best current estimate of the flow requirements of the River Deben. The modelling exercise has also been of use in a) determination of the human impact upon the flows of the Deben (33% of Q95 natural); and b) provision of a naturalised flow record. This report identifies how HYSIM has been applied to the River Deben, presents the results from modelling and lists the input data utilised.
Publisher: National Rivers Authority
Publication Date: 1995
Publication Place: Peterborough
Subject Keywords: RiversModelsFlow rateGroundwaterWater resources
Geographic Keywords: Deben (river)SuffolkEast Suffolk catchment
Extent: 9; + appendices
Total file downloads: 291

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