New Bedford River or Hundred Foot Drain

Introduction

History

Plan: Environment Agency
...............................................
Scroll down to follow the story or choose a section to jump to from the drop-down menu.

Operation and Management

This section is based largely on the EA's Ouse Washes Water Level Management Plan produced by the Halcrow Group in 2002.

Under normal conditions, water from the Bedford Ouse flows down the Hundred Foot River and is discharged to the sea via the Tidal River. Levels in the Hundred Foot River are affected by Bedford Ouse fluvial flow and King's Lynn tidal levels. There are no control structures on the Bedford Ouse, Hundred Foot River or Tidal River between Brownshill Staunch and the sea at King's Lynn.

However, water levels are affected by the operation of Earith sluice and Denver sluice. The Hundred Foot River and Bedford Ouse receive local drainage water from five Internal Drainage Board (IDB) pump stations. Most of these IDBs also transfer water in summer by gravity through slackers. The Agency manages a small gravity transfer from the Hundred Foot River into the Old West River, through Hermitage lock, to maintain water quality.

Sluices and locks

From south to north	from	to	OS grid ref	built, lift	owner/operator
Hermitage Lock	Grt Ouse	Old West			Environment Agency

Notes

Pumping Stations

From south to north	from	to	OS grid ref	built, power	owner/operator
Over					Over & Willingham IDB
Sutton Gault					Haddenham Level DCA
Oxlode					Littleport & Downham IDB
Hundred Foot					Littleport & Downham IDB

Notes: (1)

Irrigation inlet slackers

There are 17 slackers allowing water onto the Washes for irrigation, and 5 into the South Level
This section is based largely on the EA's Ouse Washes Water Level Management Plan produced by the Halcrow Group in 2002.

"The Hundred Foot River is the only available source of water for maintaining water levels in the internal ditches. The river is tidal and water can be drawn only during high tides, a period of between six and seven days each fortnight.

The total amount of water available depends on a combination of the tide height, fluvial flow and weather conditions. During dry summers there may be insufficient water available to top up ditches to the optimum level, and compromises have to be made.

Water enters the internal ditches through the seventeen inlet slackers in the Cradge Bank, the west bank of the NBR, the locations of which are shown on Figure 5. The slackers are of varying designs and dimensions, and are situated at different levels. The Hundred Foot IDB has an ongoing programme to replace or repair faulty slacker control equipment.

Water comes through the slackers into a header dyke, which runs parallel to the Cradge Bank. The aim is to bring water into the system as steadily as possible. If the slackers are opened too wide, particularly on a high tide, water enters the system too fast. Fast-flowing water carries a large silt load, erodes dams and fills ditches too quickly, causing localised nuisance flooding.

However, on a neap tide it may be necessary to open the slackers fully to bring in sufficient water over a short period. Under such conditions water levels in the header dyke will be temporarily raised, and internal water control structures must also be raised to prevent flooding. Normal IDB practice is to install gaugeboards to monitor the water levels. (continued after plan and data table)
Plan: Environment Agency
With phone in landscape view, the slacker numbers on this plan can be easily read, and then refer to IDB ref on table below for slacker details.

Name, from south to north	IDB ref	OS grid all TL	pipe diam/type	gate operation, material, type	cill OD	owner (IDB/DC)	built
Earith Hundred Ft		397 752				Haddenham Level
Black Sluice1	34	398 754	1.30m brick tunnel	screw timber penstock		Hundred Foot
Youngs Holt	32	409 768	0.225m glazed clay	handlift wood penstock		Hundred Foot
Sutton Drove	31	423 788	0.3m concrete	handlift steel penstock		Hundred Foot
Sutton Gault		425 789				Haddenham Level
Reads (near pits)	30	433 804	0.3m concrete	screw steel penstock		Hundred Foot	c1798
Witcham Gravel	28	455 825	1.30m brick tunnel	screw steel penstock		Hundred Foot
Jerusalem Drove		459 828				Littleport & D'ham
Pontoon wash	27	465 836		screw steel penstock		Hundred Foot
Common Wash	26	467 840		screw steel penstock		Hundred Foot
Ely Singers	25	475 851	0.40m glazed clay	screw steel penstock		Hundred Foot
Oxlode	22	486 864		screw steel penstock		Hundred Foot
Oxlode irrigation		472 858				Littleport & D'ham
Cambient	18	498 880	0.40m c/g steel	screw steel penstock		Hundred Foot
Dimmocks	17	5015 8846	0.15m steel	screw steel penstock		Hundred Foot
Hundred Foot		510 894				Littleport & D'ham
Hartleys	13	512 898	0.40m c/g steel	screw steel penstock		Hundred Foot
Kents	11	517 904	0.3m polypropylene	screw steel penstock		Hundred Foot
Motts	7	528 921	0.45m concrete	screw steel penstock		Hundred Foot
Deptfords	4	539 936	0.45m concrete	screw guillotine	1.60m	Hundred Foot
Charity	2a	552  954	0.45m concrete	screw guillotine	1.65m	Hundred Foot
Hagen Smart	2	562  969	0.45m concrete	screw guillotine	1.60m	Hundred Foot

Notes

Source: NRA OW WLMP, March 1996; EA OW WLMP, 2002, Fig 6  for HFW IDB refs.

(text continuned from before plan)
Once water has entered the system it is necessary to distribute it in the most efficient and equitable way. Water in the header ditch can flow in either direction. Each slacker feeds a defined section of the Washes. The area of the different sections varies considerably (see Appendix 10c). In order to get water to the most distant ditches it is necessary to use the temporary head created by tidal influx to best effect by expediting its passage through dams, culverts and water control pipes. The controls in ditches nearest the inlet are set at the highest position early on in the cycle, to enable water to flow into the more distant ditches. Ideally the most distant ditch should start to take water at the same time as the nearest one, although in practice the nearer ditches usually receive water earlier.

There is a natural, albeit small (0.3 to 0.45m), gradient ac`ross the Washes from the Hundred Foot River to the Old Bedford/Delph River. Most ditches crossing the Washes have four or five water control points along their length, including one at the junction with the Cradge Ditch and another at the bottom of the ditch by the Old Bedford/Delph River. In years with summer floods, only the upper two or three sections of ditches have required topping up, as high water levels in the Old Bedford/Delph River have helped to maintain ditch levels in the lower part of the system.

When river levels drop, the lowest part of the ditches need topping up. Most ditch outfalls have control structures, which are set during the summer to ensure that no water flows into the Old Bedford/Delph River.For the slackers and ditch systems operated by the Hundred Foot Washes IDB, annotated maps on a 1:10,000 scale have been produced giving outline details of the current working procedures. These are not included in this document, as they are working documents subject to continual amendment, but further information can be obtained from the Hundred Foot Washes IDB Wash Superintendent at the RSPB Ouse Washes Reserve."

From south to north	No.*	inlet from	to	OS grid ref	built/rebuilt	owner
Earith 100ft		NBR/100Ft				Haddenham Level DCA
Black Sluice	34	NBR/100Ft	Washes			Hundred Foot IDB
Youngs Holt	32	NBR/100Ft	Washes			Hundred Foot IDB
Sutton Drove	31	NBR/100Ft	Washes			Hundred Foot IDB
Sutton Gault		NBR/100Ft				Haddenham Level DCA
Reads	30	NBR/100Ft	Washes			Hundred Foot IDB
Witcham Gravel	28	NBR/100Ft	Washes			Hundred Foot IDB
Jerusalem Drove		NBR/100Ft				Littleport & Downham IDB
Pontoon Wash	27	NBR/100Ft	Washes			Hundred Foot IDB
Common Wash	26	NBR/100Ft	Washes			Hundred Foot IDB
Ely Singers	25	NBR/100Ft	Washes			Hundred Foot IDB
Oxlode	22	NBR/100Ft	Washes			Hundred Foot IDB
Oxlode Irrigation		NBR/100Ft	L&D IDB			Littleport & Downham IDB
Cambient	18	NBR/100Ft	Washes			Hundred Foot IDB
Dimmocks	17	NBR/100Ft	Washes			Hundred Foot IDB
Hundred Foot		NBR/100Ft	L&D IDB			Littleport & Downham IDB
Hartleys	13	NBR/100Ft	Washes			Hundred Foot IDB
Kents	11	NBR/100Ft	Washes			Hundred Foot IDB
Motts	7	NBR/100Ft	Washes			Hundred Foot IDB
Deptfords	4	NBR/100Ft	Washes			Hundred Foot IDB
Charity	2a	NBR/100Ft	Washes			Hundred Foot IDB
Hagen Smart	2	NBR/100Ft	Washes			Hundred Foot IDB

*.from fig 6, schematic water movement in OW WLMP by Halcrow

Bridges

Name or location	OS map ref	type	construction	built rebuilt	access
Earith
Sutton Gault
Mepal by-pass			Reinforced concrete	1984?
Railway		Metal	Truss	1927
Suspension Bridge			steel & reinforced concrete deck	1995

Pubs & Inns

name	OS map ref	location
The Anchor		Sutton Gault (East)
Three Pickerells		Mepal

Data Sources

note	date	publication
1
2
3
4
5
6
7
8
9
10
11
12
13

 

Notes and sources

source
1
2