 |
| Titel |
Spatial variations and implication of stormwater runoff pollution from rapidly urbanizing Shiyan reservoir catchment in China |
| VerfasserIn |
H. P. Qin, X. Y. Yu, S. T. Khu |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250020232
|
|
|
|
|
|
| Zusammenfassung |
| Shiyan Reservoir catchment is located in the rapidly urbanizing coastal region of Southeast
China. The catchment is a mixture of agricultural/industrial/residential land use. It has six
sub-catchments named WJZ, SKL, BKW, SYH, MBS and YNK with impervious cover
percentage varied from 85% to 6%. The considerable spatial variations of land use patterns
and urbanization levels are deemed to have great effect on storm runoff pollution
management in the catchment.
Since there is no gauge for continuous hydrological monitoring in each sub-catchment, in
this study, temporary monitoring sites were set at the downstream section of each
sub-catchment in Feb-May 2007 to measure stream flow and associated water quality, e.g.
COD, NH3-N, TP, SS, TN, BOD5. In order to make up for data insufficiency due to relatively
low frequency monitoring, IHACRES and exponential wash-off model were applied to fit the
monitoring stream flow and water quality time series data. Three indicators, event pollutant
loads per unit area (EPL), event mean concentration (EMC) and pollutant loads
transported by the first 50% of runoff volume (FF50), were used to describe the runoff
pollution characteristics for each pollutant in each of six sub-catchments. The values
of these three indicators were calculated in terms of fitted time series data using
two very different rainfall events, a light rain and a heavy rain event. Furthermore,
the spearman’s rank correlation coefficients were used to discover the strength of
links between runoff pollution spatial variations and land use patterns or urbanized
levels.
The results indicated that: 1) in light rainfall event similar spatial variation trend were
found for the EPL (or EMC) indicators of all the pollutants considered in this study. However,
in heavy rainfall event, different spatial variations were found for the EPL (or EMC)
indicators of different pollutants. The characteristics imply that during light rain, all
pollutants’ loads are mainly washed off from impervious land covers; however, in heavy
rainfall event, some pollutants’ (e.g. TP, SS) loads also come from pervious land covers. 2)
EPL indicators of COD and NH3-N have strong positive-correlation with percentage of
residential land use in sub-catchment. It implies that residential land use pattern is the
main source of COD/NH3-N loads. 3) The intensity of first flush (FF50) increase
generally with increase of residential land use percentage. However, FF50 is also
affected by the shape of the residential land use and its topological relation with
river.
Keywords: spatial variation; runoff pollution; urbanization; land use; rainfall intensity |
|
|
|
|
|
|