47015 - Tavy at Denham / Ludbrook

Grid Reference:	20 (SX) 476 681
Operator:	EA
Local number:	4461003
Catchment Area:	197.3 km²
Level of Station:	10.0 mOD
Mean flow:	6.90 m³s^-1
95% exceedance (Q95):	0.991 m³s^-1
10% exceedance (Q10):	16.8 m³s^-1
61-90 Av. Ann. Rainfall:	1559 mm

Sample Hydrograph of Gauged Daily Flows

Flow Duration Curve for Gauged Daily Flows

Station Description

Unconventional control comprising a flume set within shallow (0.3m) wing walls which curve through 90 deg. W to fill the whole channel (20m). Cableway spans 32m. Responsive, well contained. Good rating but greater uncertainty at higher flows due to lack of gaugings. Low flows dominated by abstractions for hydropower station and public water supply for Plymouth and the Morwellham canal.

Catchment Description

Responsive catchment drains from western flank of Dartmoor Granite plateau; valleys are steeply incised and forested below Tavistock. Land use: moorland, rough grazing and low grade agriculture.

Factors Affecting Runoff

Natural to within 10% at the 95 percentile flow.

River Flow and Catchment Rainfall on the National River Flow Archive

Gauged Daily Flows (gdf):	1981 to 2008
Naturalised Daily Flows (ndf):	1957 to 1985
Monthly Catchment Rainfall (rnf):	1981 to 2008

Datatype	1950s										1960s										1970s										1980s										1990s										2000s

gdf
ndf
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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