67020 - Dee at Chester Weir

Grid Reference:	33 (SJ) 408 659
Operator:	EA
Local number:	67420
Catchment Area:	1816.8 km²
Level of Station:	4.3 mOD
Max. Altitude:	884.0 mOD
Mean flow:	29.71 m³s^-1
95% exceedance (Q95):	3.739 m ³s^-1
10% exceedance (Q10):	80.45 m³s^-1
61-90 Av. Ann. Rainfall:	1111 mm

Sample Hydrograph of Gauged Daily Flows

Flow Duration Curve for Gauged Daily Flows

Station Description

Velocity-area station u/s of ancient weir liable to tide over-spilling. 30% of time unsuitable hydraulically for continuous flow record. Superseded by 067033 (Chester Suspension Bridge). Hifs not archived.

Catchment Description

Geology: upper catchment impermeable Lower Palaeozoic rocks with intermittent Drift cover. Below Llangollen, R. Dee crosses Carboniferous L'st escarpment and outcrops of Cefn-y-Fewd S'st, Coal Measures and Sherwood S'st, providing many artesian areas in lower catchment.

Factors Affecting Runoff

Reservoir(s) in catchment affect runoff.
Regulation from surface water and/or ground water.
Runoff reduced by public water supply abstraction.
Runoff influenced by groundwater abstraction/recharge.
Runoff increased by effluent returns.
Runoff reduced by industrial/agricultural abstraction.

River Flow and Catchment Rainfall on the National River Flow Archive

Gauged Daily Flows (gdf):	1984 to 1998
Monthly Catchment Rainfall (rnf):	1961 to 2008

Datatype	1960s										1970s										1980s										1990s										2000s

gdf
rnf

For many stations monthly peak flows are also archived. When daily flow data are not available monthly mean flows may be held on the National River Flow Archive. See Data Holdings for further information.

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