Horstergrub sediment management, Belgium

General

National Id

Belgium_02

Site name

Gravenvoeren

Summary

This measure is located near the village of Gravenvoeren in eastern Belgium. It was a low-cost project to retain mudstreams/erosion consequences by the building of a horizontal dyke/dams at the bottom in the valley, which will retain the water longer in the valley, so reducing runoff and sediment transport to the villages downstream. Additionally they changed crop growing from corn to grasslands to help reduce erosion.

Location description

The site is located in a rural location on the Horstregrub stream, upstream of the village of Gravenvoeren. It is located in the catchment of the River Voer, which is itself a tributary of the Meuse.

NUTS Code

Prov. Limburg (BE)

RBD code

BEMaas_VL

Transboundary

Data provider

Heather Williams and Chris Binje, AMEC

Source(s)

Pilootprojecten Stroomgebied Voer

NWRM(s) implemented in the case study

Meadows and pastures

Basins and ponds

Longitude

5.7720445

Latitude

50.7585409

Site information

Climate zone

cool temperate moist

Mean rainfall

800

Mean rainfall unit

mm/year

Average temperature

Type

Case Study Info

Light or indepth?

Light

Average slope range

5-10%

Vegetation class

Hilly grasslands

Monitoring maintenance

Monitoring impacts effects

Performance

Performance impact estimation method

Unknown

Performance impact estimation information

n/a

Design & implementations

Application scale

Field Scale

Age

Performance timescale

Immediate

Design capacity description

Design capacity of the retention pond is 6.000 m3.

Constraints

There are no specific constraints to the application of this measure type, which is a simple method of runoff capture

Crop rotation

The land cover was changed from seasonal crop rotation to grasslands under an agreement between the farmer and the local community.

Design contractual arrangement

Arrangement type	Responsibility	Role	Comments	Name

Design consultation activity

Activity stage	Key issues	Name	Comments

Design land use change

Land use change type

Design authority

Authority type	Role	Name	Comments
Other	Other	Province of Limburg	The Belgian province of Limburg	View
Other	Other	WRO	The WRO (Waterschap Roer en Overmaas) is the local water authority on the Dutch side of the border. Although not directly involved, RWO Was responsible for a different pilot project upstream on the Horstergrub, also contributing to decreasing the flood risk.	View
Other	Initiation of the measure	Commune of Voeren	The local community of Voeren was involved as a full partner, initiating and financing the NWRM and appointing the VMM as executional officer of the program. The community of Voeren was furthermore involved in the entering into compensation agreements with local farmers.	View
Regional / sub-national water authority	Implementation	VMM	VMM was appointed as the executing agent of the project, including the detailed design.	View

Lessons, risks, implications...

Key lessons

Low-cost measures can make a significant local improvement to runoff and sediment load problems.

Success factor(s)

Success factor type	Success factor role	Comments

Financing

Financing type	Comments

Barrier

Barrier type	Barrier role	Comments

Driver

Driver type	Driver role	Comments
Past flooding events	main driver	Past flooding events have occurred in the village of Gravenvoeren	View

Financing share

Financing share type	Share	Comments

Policy, general governance and design targets

Policy description

In the area of the project a lot of erosion happens during heavy rainfall events. As there is no natural stream or other way of transporting rainwater away, surface runoff occurs over the area, causing mudstreams or floodings in the village downstream. Measures to prevent this from occurring were therefore needed.

Part of wider plan

Policy target

Target purpose
Erosion Control	View
Runoff control	View

Policy pressure

Pressure directive	Relevant pressure

Policy area

Policy area type	Policy area focus	Name	Comments

Policy impact

Impact directive	Relevant impact

Policy wider plan

Wider plan type	Wider plan focus	Name	Comments
Regional	Water	Aquadra	Aquadra had as a purpose to strive for clean water conditions across regional and national borders. Partners in the project included the Dutch and Belgians provinces of Limburg, province of Liege, regional water authorities from these 3 provinces and the German city of Aachen.	View

Policy requirement directive

Requirement directive	Specification

Socio-economic

Costs investment

55000

Compensations scheme information

Some compensation was agreed with the landowner to change the landuse to pasture

Information on Ecosystem improved biodiversity

The landuse upstream has been changed from crops to grassland, which allows an increase in diversity compared to the previous land use

Information on Ecosystem provisioning services

n/a

Ecosystem impact climate regulation

Not relevant for the specific application

Information on Ecosystem impact climate regulation

n/a

Biophysical impacts

Information on retained water

6000 m3 total storage volume

Information on increased water storage

6000 m3 total storage volume, compared to zero previously

Ecosystem erosion control

Information on Ecosystem erosion control

Slows runoff, allowing sediment deposition and reducing the risk of further erosion downstream

Water quality overall improvements

Positive impact-WQ improvement

Information on Water quality overall improvements

Reduction in transfer of sediment and associated nutrients or other pollutants downstream, by allowing sediment deposition in the storage area

Information on Ecosystem erosion control impact

Not quantified

Soil quality overall soil improvements

Positive impact-SQ improvement

Information on Soil quality overall soil improvements

The Voeren area is an area with significant erosion problems, causing mudstreams in the center of the village of Gravenvoeren. As a result of this NWRM, less good quality soil will be eroded and transported downstream.

Partners