10.4122/1.1000001582
Dimova, G.
G.
Dimova
Ballard, B. W.
B. W.
Ballard
Kellagher, R.
R.
Kellagher
A critical appraisal of retention pond sizing criteria for water quality treatment
DTU Library, Technical University of Denmark (DTU)
2005
Conference full text
Antecedent rainfall events
residence time
retention ponds
SUDS
water quality
HR Wallingford
2005
en
10.4122/1.1000001581
application/pdf
This paper presents a critical appraisal of sizing criteria for permanent retention pond volumes in the UK, together with recommendations for a more holistic approach that considers both climatic influences and natural environmental processes. High frequency rainfall events are generally significantly smaller than the design pond volume (Vt) and thus, for most storms, the proportion of turnover of the permanent pool will be less than 1. It will therefore be the quality of the permanent pool rather than the influent that will tend to determine the quality of effluent discharged to receiving waters. The extent of natural physical and biological processes occurring in the pond are likely to be dependent on the residence time of the water. Water quality of a treatment train of small, vegetated ponds has been studied at a site in the UK. This study indicates that effluent nutrient concentrations can show negative relationships with residence time. The water quality shows good correlation with an index of antecedent wetness and it is suggested that this parameter may be a key influence on the performance of ponds with respect to nutrient removal. Antecedent wetness and residence time vary significantly with both season and geographical location.