See: Recording stations on Stour daily Stour levels Latest levels Canford sluice Durweston Mill hatches

Measuring the delay between rain falling and level crest arriving at different places along a river. Approx. calibration between these places and Bear Mead. Transit speeds calculated from distance along the river. Dorset Stour used over 47 miles. Data from Environment Agency Level recording stations, BBC weather radar records, and Google Earth tools.

Recording Stations along Dorset Stour: Gillingham,Hammoon, Blandford, Wimborne. Gillingham-Hammoon=21.13 miles Hammoon-Blandford=10.76 miles Blandford-Bear Mead=11.92 miles Bear Mead-Wimborne=3.23 miles Total=47.04 miles along river.

Catchment area of the Dorset Stour, with Recording Stations and distance between stations along river in miles.

Peak caused by heavy rain (c34mms), and its decreasing delay as it propagates down a widening river, which had low water level due to near-drought conditions.

31hrs delay 21miles 0.7mph 12hrs delay 11miles 0.9mph 19hrs delay 15miles 0.8mph

Durweston Mill

effect of hatches opening

River Stour ||||| ||||| 7.6 miles ||||| Durweston Mill ||||| 3.2 miles ||||| ||||| 15 miles 22 hrs ||||| ||||| River Stour

Stour levels and delays Levels taken from public websites for: Gillingham | Hammoon | Blandford | Wimborne and the author's own measurements for Bear Mead. Distance along river in miles using Google Earth: Source(0)-Gillingham(7.22)-Hammoon(28.32)-Blandford(39.12)-Bearmead(51.02)-Wimborne(54.25)-Sea(71.95) Delay varies greatly with height of water in river. Delay (approx) in hours (for low crest): Rain(0)-Gillingham(4)-Hammoon(22.5)-Blandford(27.5)-Bearmead(33)-Wimborne(34.5)-Sea Gillingham Hammoon Blandford Bear Mead Wimborne 72m 40.900m 31.0m c19 m 14.603m AOD ID=3296 ID=3306 ID=3305 none ID=3302 ST805266 ST820147 ST88330595 SY986993 SZ024992 All times in GMT

Effect of opening Durweston hatches

Hatches at Durweston Mill. Each arch contains 3 hatches: total 9 hatches River rises 11 cms in 4 hrs at 2200 hrs on 17 Jul 2011, as 3 of 9 Durweston Mill hatches are opened then closed because of weed blockage. Peak of 0.51 is followed by a trough of 0.25, 9 hours later. Peak reached Wimborne (15 miles) after 22 hours delay (0.69 mph), propagation time is very slow because the river is unusually low.

Progress of Durweston Slosh downstream 1. Slosh first recorded at Blandford. Hatches opened 1800 hrs then closed 0800 hrs next day, river drops then recovers. 2. Slosh next recorded at Bear Mead as 144 at 1600 (on max) and 135 at 1300 (on min). 3. Slosh last recorded at Wimborne. Average delay 22 hours over 15 miles from Blandford to Wimborne (0.68 mph).

See: Recording stations on Stour daily Stour levels Latest levels Canford sluice Durweston Mill hatches

This disturbance was confirmed by phoning Durweston Mill on 22 Aug 2014. The cause was raising the hatches of the Mill about 2100 hrs on 21aug2014, preparatory to clearing out jammed flotsam next morning.

DURWESTON Mill

(3.2 miles 3 hours = 1.1 mph)

(12 miles 12 hours = 1.0 mph)

BEAR MEAD           0800

(3 miles 3 hours = 1.0 mph)

(7 miles 7 hours = 1.0 mph)

(3 miles 2 hours = 1.5 mph)

(TOTAL: 28.2 miles 27 hours = 1.04 mph)

Compiled, formatted, hyperlinked, encoded, and copyright © 2011, John Palmer, All Rights Reserved.