SUDS Performance Data 2003

Using the partnership's 2003 water quality sampling results, the Environment Agency (EA) analysed SUDS performance in 2003, comparing the newly created SUDS with two well-established on-line ponds further downstream.  

In brief, the EA's analysis of our water quality sampling for 2003 found:

BOD = biochemical oxygen demand

DO = dissolved oxygen

The 'significant decreases' in faecal coliforms, ammonia and BOD at the SUDS site is a triumph!  Evidence of this can be seen in the graphs below.

Decreases in suspended solids was good, but couldn't be called significant.  Nitrates are not a significant contributing factor to Bourne stream diffuse pollution problems (classified as 'moderately low') and so those results are not a disappointment.

The increases in coliforms, ammonia and suspended solids at Coy Pond are the result of the polluting effects of large numbers of waterfowl on a typical municipal pond; in contrast the SUDS at Alderney and Alder Road pond, whilst both supporting some waterfowl, feature reedbeds and vegetated margins which have a beneficial effect on water pollution.  

All ponds appear to have a detrimental effect on levels of dissolved oxygen; this can be overcome by creating weirs and other oxygenating features in-stream.  

Charts below illustrate mean data collected over 15 weeks between 28 May - 10 September, including the sampling during heavy rainfall on 28 August (graphs showing evidence of successful 'first flush' treatment by SUDS on this day is shown separately here)