Floodbreaking hedgerows in Southern France | Natural Water Retention Measures

General

National Id

France_01

Site name

Lèze River Basin

Summary

The Lèze is a river located in the South of France, near the Pyrenees, on the French departments Ariège and Haute-Garonne. The case study concerns the implementation of floodbreaking hedges, which are located across the flood plain of the Lèze and are regularly spaced (every 300 to 500 metres). Partially obstructing the flow, such hedges can slow down running water and dissipate its energy. The project has been financed by the SMIVAL (20%), French State, local authorities, ERDF and the Water Agency (80% for all).

Light or indepth?

In-depth

The in-depth description of the case study

cs-fr-1-final_version.pdf

NUTS Code

Midi-Pyrénées

RBD code

FRF

Transboundary

Data provider

Guillaume MICHEL, ACTeon

Source(s)

SMIVAL Rapport d'activité 2009 (Activity report 2009)

SMIVAL Rapport d'activité 2010 (Activity report 2010)

SMIVAL Rapport d'activité 2011 (Activity report 2011)

SMIVAL, Rapport d'activité 2012 (Activity report 2012)

SMIVAL Rapport d'activité 2013 (Activity report 2013)

NWRM(s) implemented in the case study

Buffer strips and hedges

Longitude

1.362

Latitude

43.254

Site information

Climate zone

cool temperate moist

Mean rainfall

795,3

Mean rainfall unit

mm/year

Average temperature

13,1

Mean runoff

Mean runoff unit

600 - 750 mm

Average runoff coefficient

0,26

Type

Case Study Info

Monitoring maintenance

Monitoring impacts effects

Administrative annual costs

55000

Administrative annual cost information

For the period 2006-2011, costs for facilitation (all actions including floodbreaking hedgerows) supported by the SMIVAL amounted to 326 336 € (ranging from 21 855 € in 2006 to 70 655 in 2009). In comparison to other actions implemented by the SMIVAL, floodbreaking hedgerows represent only a small share of SMIVALs budget (1.4 %). It can hence be assumed that facilitation costs related to floodbreaking hedgerows represent also only a small share of the total facilitation costs.

Performance

Performance impact estimation method

Unknown

Performance impact estimation information

No performance evaluation

Design & implementations

Application scale

River Basin

Installation date

2009-03

Lifespan

Age

Performance timescale

5 - 10 years

Area (ha)

35000

Area subject to Land use change or Management/Practice change (ha)

1.3

Size

6000

Size unit

Design capacity unit

Constraints

Presence of irrigation or drainage equipement

Peak flow rate

144

Public consultation

Contractural arrangements

Design contractual arrangement

Arrangement type	Responsibility	Role	Comments	Name
Organisational arrangement			Protocol between the SMIVAL and the Chambers of agriculture defining land policy (for example purchase of arable land for hedge planting) Four options are available to farmers: agreement with the SMIVAL, servitude, renting and buying	Protocol for land policy
Contractual agreement			The Framework agreement has been signed in August 2008 by the SMIVAL and its partners (French State, Adour-Garonne Water Agency, Regional council, General councils of Ariège and Haute-Garonne). This Framework agreement works for the implementation of all actions included in the PAPI for the period 2008-2016.	Framework agreement

Design consultation activity

Activity stage	Key issues	Name	Comments
		Public meetings	Several public meetings took place from 2009. They aimed at presenting the actions programme (including hedgerows) to the inhabitants. For each meeting, about 20 participants were presents. The SMIVAL also met inhabitants and local associatiations.
		Meetings with farmers	Numerous meetings took place with farmers and landowners who may be concerned by planting floodbreaking hedges. The main issue was to explain implementation of this action and to define the associated land policy.
		Consultation with local authorities	In 2009, local authorities (mayors) have been met in order to know about the implementation of the actions programme (including hedges) at the villages' level. Mayors also had the opportunity to express their expectations.
		Consultation with technicals	The two local Chambers of agriculture are involved in defining the protocole regarding the land policy. Technical partners (for example deconcentrate technical state services and water related public agencies) have been consulted by the SMIVAL when actions of the PAPI have been presented and implemented.
		Public inquiry	A public inquiry has been carried out in 2011. The response brief has been published in August 2011.

Design land use change

Land use change type

Design authority

Authority type	Role	Name	Comments
Local water authority	Initiation of the measure	SMIVAL (Syndicat Mixte Interdépartemental de la Vallée de la Lèze)	The SMIVAL (Syndicat Mixte Interdépartemental de la Vallée de la Lèze - an association of 24 communes localised in the Lèze's valley) has been created in 2003. It is responsible for leading, for defining and for implementing actions for a qualitative and quantitative use of the Lèze and its tributaries and for preventing its floods.
Farmers	Determination of design details of the measure	Chambres d'agriculture
	Implementation	Technical Committee	The Technical Committee supervises the implementation of the PAPI. It is presided by a sub-prefect and the president of the SMIVAL. Techical Committee includes the SMIVAL, local authorities, deconcentrate technical state services, public agencies for water management (Onema, Agence de l'eau Adour-Garonne) Chambers of agriculture.

Lessons, risks, implications...

Key lessons

This case study shows the implementation of floodbreaking hedges across the flood plain of the Lèze, a river in the South of France. A land policy has been agreed with farmers and land owners for the implementation of the hedges as well as numerous participation activities.

Success factor(s)

Success factor type	Success factor role	Comments
Attitude of relevant stakeholders	main factor	An enabling factor for involving local stakeholders is the overlap of global issues and local events. For example, the involvement of farmers is higher when they see mudslides in their fields than when they hear about slowing down the peak flow.

Financing

Financing type	Comments
National funds	For the period 2007-2011: 4 425 € from the French state.
Other	For the period 2007-2011: 8970 € from SMIVAL (self-financing; each member of the SMIVAL is involved in its financing).
Local funds	For the period 2007-2011: 1008 € from the General Council and 2144 € from the Regional Council.
EU-funds: Cohesion and regional development funds	For the period 2007-2011: 456 € from the ERDF programme.
Other	For the period 2007-2011: 5306 € from the Adour-Garonne Water Agency.

Barrier

Barrier type	Barrier role	Comments
Other	secondary barrier	Access is difficult to data about farmers possessing land in the Lèze valley. It is therefore more difficult for the SMIVAL to target these farmers and to invite them to meetings, for example. This information is confidential and cannot be easily spread.
Attitude of relevant stakeholders	main barrier	Implementation of floodbreaks is based on voluntary farmers.

Driver

Driver type	Driver role	Comments

Financing share

Financing share type	Share	Comments
European funds	2,04999995231628	According to the activity report 2012, financing from the FEDER programme was still ongoing when the report was written.	View
National funds	57,75		View
Private funds	40,2	For the period 2007-2011, 40,2 % of financing comes from the SMIVAL. Up to April 2014, financing from the SMIVAL represents about 20 % of the total financing.	View

Policy, general governance and design targets

Policy description

The main targeted problem is flood. Floodbreak hedgerows aim at slowing down flood peaks. Hedgerows are located across the flood plain, perpendicular to the river, and they are regularly spaced every 300 to 500 metres.

Part of wider plan

Policy target

Target purpose
Peak-flow reduction
Runoff control
Erosion Control

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
Local	Water	PAPI de la Lèze : Programme d'Actions de prévention contre les inondations de la Lèze (Actions Programme for preventing floods of the Lèze river)	The PAPI is an action programme designed for fighting floods in the Lèze river bassin. Planting floodbreaking hedgerows is one of these actions. The PAPI has been approved by the French Ministry for Ecology, Sustainable Development and Territorial Planning.

Policy requirement directive

Requirement directive	Specification

Socio-economic

Costs land acquisition

5000

Costs land acquisition unit

€/ha

Costs land acquisition information

Four types of agreements with the SMIVAL were proposed to farmers and land owners. For one option, the SMIVAL had to buy the land from the owner. The price of land depends on the crop (arable lands or permanent grasslands) and on the département. In Ariège, prices are 5000 €/ha for arable land and 2500 €/ha for permanent meadows. In Haute-Garonne they reach 6000 €/ha and 3000 €/ha, respectively.
This option was never chosen by land owners.

Costs total

75000

Costs total information

Financing comes from the French State, the SMIVAL, local authorities, ERDF and the Water Agency. Up to now, about 75 000 € have been spent for floodbreaks. About 20 % of the financing comes from the SMIVAL and 80 % from other financing partners.

Between 2009 and 2012, 3020 linear metres of hedgerows have been planted (including 520 linear metres for the two test hedgerows) for a total cost of 47 870 € (costs for hedgerows which have been planted later are not taken into account).
Costs are distributed as follow:
- Technical study: 9 240 € in 2007
- First test hedge (in Montaud): 4 221 € in 2008 and 3 532 € in 2009
- Second test hedge (in Artigat): 3 420 € in 2010
- Hedge planting 2011-2012: 27 456 € in 2011 and 2012
Cost of one linear metre of hedge : 11 € as planned by the PAPI. But for the test hedgerows, costs reached 45 to 60 € per linear metre.

Compensations annual information

Payment depends on the agreement between farmers/landowners and the SMIVAL. In some cases, there is no payment. There may be a payment to landowners when arable land is bought or rent by the SMIVAL. There may also be a payment to farmers when new hedgerows disturb the organisation of the farmer.

Compensations nr beneficiaries information

Landowners and/or farmers. There is no number available.

Compensations scheme information

Payment depends on the agreement between farmers/landowners and the SMIVAL. In some case, there are no payment. There may be a payment to landowners when arable land is bought or rent by the SMIVAL. There may also be a payment to farmer when new hedgerows disturb the organisation of the farmer.

Information on Ecosystem improved biodiversity

N/A info

Ecosystem provisioning services

Information on Ecosystem provisioning services

Provision of wood and food (fruit trees in the hedges).

Information on Ecosystem water supply

N/A info

Ecosystem impact climate regulation

Not relevant for the specific application

Biophysical impacts

Information on Peak flow rate reduction

According to a hydrological model: In the case where the flood plain of the Lèze would be covered by regularly spaced floodbreaking hedgerows, the peak flow of flood events could be reduced by 25% in comparison to the same river basin with field crops. In fact, the river basin already has hedges (about 900 km) and it will not be possible to achieve a landscape with a very dense network of hedges. The model only shows a trend.

Ecosystem erosion control

Information on Ecosystem erosion control

Slowing down water runoff should help to decrease soil erosion in the flooding plain.

Water quality overall improvements

Not relevant for this application

Information on Ecosystem erosion control impact

Local positive impacts on soil erosion can be seen, but there is no assessment nor quantification

Soil quality overall soil improvements

Not relevant for this application