EPIDOR
Action Programme for
Prevention of Flooding
in the Dordogne basin
The issues and proposals
January 2007
PAPI Dordogne: Programme of Actions for the Prevention of Inondations (i.e. floods)
SUMMARY
Introduction................................................................................................................
I.1
I.2
I.3
I.4
The fight against flooding - everybody’s responsibility.........................
The issues at stake in the basin..................................................................
The objectives of the PAPI Dordogne..................................................
The strategies adopted.........................................................................
3
3
5
5
6
Chapter 1
Reinforcing the forecasts and the warning system............................ 7
Chapter II
Lessening the flood risks................................................................
8
II.1. Retaining the water upstream of the sectors concerned...................................
II.2 Restoring the natural draining capabilities........................................................
II.3 Restoring and maintaining the flow areas.........................................................
8
8
9
Chapter III
Protecting property and people.....................................................
10
Chapter IV
Reducing the vulnerability.............................................................
11
Chapter V
Anticipating the floods thanks to collective organisation.................
12
Improving knowledge about the floods and consequent risks...........................
Watching the dams and their management.......................................................
Ensuring that seasonal activities are taken more into account..........................
Encouraging the production of crisis management devices..............................
Formulating flood risks and making people more aware of them......................
Implementing the action prorgramme................................................................
12
13
13
14
14
14
V.1
V.2
V.3
V.4
V.5
V.6
Introduction
I.1 The fight against flooding - everybody’s responsibility
The fight against flooding involves many different parties: the State, the local elected bodies
and the mayors, as well as individuals... In their own fields, all participate in the forecasting
function (for instance, measuring water heights), the protection of people and property (crisis
management), and actual prevention (better management of the territory, memories of
previous risk situations).
Organisational diagram of those involved in the fight against flooding in the Dordogne basin
Si on peut les changer, voici les légendes pour les petits mots dans les panneaux en blanc :
CRUDOR
- Informs
DIREN
- Informs
(atlas)
Prefectures
- Draw up the PPRI (Plans for
Prevention of Flood Risk
- Take over management
of the crisis if it goes
beyond local level
Mayors
- Draw up town planning
documents
- Manage the crisis
- Manage the post-crisis period
Conseils, etc.
- Overall management
---o0o--(petits mots, noir sur gris)
supply to
warn
State
Elected bodies
warn
consult
back-up
assists
co-ordinates
assists
warn
consult
The State provides for the forecasting and warning systems in the major sectors. Based on
the data collected by the network of stations measuring the water depths, the Flood
Forecasting Services for the Dordogne and Atlantic Littoral undertake the task of prediction
and, if necessary, inform the prefectures on the hydrological situation in the basin and the
developments expected.
The prefectures alert the mayors if the current or predicted
warning levels will be exceeded. For the general public, the State provides flood information
on these websites: www.vigicrues.ecologie.gouv.fr and
www.dordogne.equipement.gouv.fr/crudor/.
The State has a hand in the prevention of flooding because it draws up the PPRI, Plans for
the Prevention of Flood Risk, which determine the town planning regulations. (At present,
there are 117 communes with approved PPRI and 177 communes with PPRI that have been
prescribed or are in course of being drafted.) The Regional Directorates for the Environment
(DIREN) arrange for the production of atlases of the zones liable to flooding and providing
information on the nature of the risks. These can be obtained by anyone interested (and are
available on internet in the Midi-Pyrenees region).
The State is also responsible for management of the crisis when this goes beyond the local
level, which is frequently the case with floods.
Each mayor has responsibilities in view of his powers to maintain order and ensure the
safety of those under his administration (art. L.2212 of the General Code for local elected
bodies, reinforced by the law of 30.07.03). He must take all necessary measures for
protecting the inhabitants by:
-
installing the means for prevention of major risks
-
preparing the crisis management, particularly thanks to the Communal Safeguard Plan
-
ensuring the population’s protection against the major risks
-
alerting the inhabitants
-
directing rescue operations and taking safety measures
-
calling for the Prefect’s intervention when the disasters spread beyond the local level
-
producing safety information for the inhabitants of his commune
As regards the prevention of floods, the mayor is also responsible for the production of
town planning documents.
The other elected bodies involved in managing the territories (such as the administrative
regions, the départements and the groupings of communes) likewise have an essential role
to play in the prevention of flooding. For example, they can maintain escape channels for
the floods, ensure the upkeep of the waterways and carry out local protection work.
A law passed in 2003 gives EPIDOR and similar bodies a specific mission to prevent flooding
in the river basins as a whole - a mission crystallized in the action programme outlined in
this document.
The programme sets out to reinforce the efficacy of the obligatory measures
and to organise a wide range of other actions, throughout the basin, which will help to lessen
the overall flood risk.
Individual inhabitants must respect the regulations relating to town planning, to avoid
aggravating the vulnerability of the dwellings. When floods occur, they can keep abreast of
the latest information by consulting the Vigicrues and Crudor websites. They should obey
safety instructions and initiate their own protective measures (storing objects in watertight
containers, for instance).
Business companies can limit their vulnerability by anticipating the likely effects of flood
crises (e.g. through diagnosing probable weak spots).
I.2 The issues at stake in the basin
In the Dordogne basin, 64% of the population, i.e. some 700,000 inhabitants living in one of
the 500 communes subject to flood risk, are potentially affected by the direct or indirect
impact of a major flood. Of these, 8% of the population, or 85,000 inhabitants, live directly
on a flood plain.
Where buildings and other constructions are concerned, the principal threats are centred on
the rivers Vézère, Isle and the down-stream sector of the Dordogne - specifically the
built-up areas around Brive and Périgueux and the Lower Dordogne territory between
Bergerac and Ambès. The Aurillac, Middle Dordogne and down-stream Dronne sectors also
face sizeable challenges. Outside these territories, the threats are more diffuse in nature
(for example, occasionally affecting the communes of La Bourboule in the Upper Dordogne
or Brantôme on the Dronne).
The vulnerability of both built-up areas and economic activities is already very considerable,
therefore, and is liable to get worse because building construction on the flood plains
continues to expand more quickly than anywhere else.
Map showing the areas in the Dordogne basin principally under threat
It is essential for particular attention to be paid to the false sense of security afforded by the
Dordogne’s big hydroelectric dams, which cut down the small and medium floods. But this
protection depends on the amount of water the dams are able to handle and is thus in no
way a guarantee in the medium or long term.
I.3 The objectives of the PAPI Dordogne
In 2002, awareness of the flood risks throughout France led the Ministry for the Environment
and Durable Development to launch an appeal for the submission of integrated programmes
for the fight against flooding. The proposals for the Dordogne basin were accepted and a
study carried out in 2005-2006 resulted in the definition of an action programme.
Known for short as the PAPI Dordogne (Programme of Actions for the Prevention of
Inondations), its aim is to implement measures integrated within the framework of balanced
management of the water resources. In particular, it entails the establishment of synergies
between the fight against flooding, management of the territory, preservation of the aquatic
ecosystems and wet zones, and the development, protection and valorization of the water
resources.
For example, a majority of the flood plains are listed as areas of outstanding
ecological interest: the issues involved in preserving the Natura 2000 sites can thus find an
echo in the policies for leaving the rivers with lateral space so that the flood waters can
spread out, enabling the river to dissipate its energy in beating against the banks and
displacing pebbles and other solids - which in turn enables its course to evolve naturally. In
like vein, coherent upkeep of the waterways will aid their free flow.
The positive effects of floods
They are part of the dynamic of the waterways, contributing above all to:
-
carrying down solids such as pebbles and sand, which plays an important role in the
morphology of the rivers
-
fertilisation of the agricultural lands, through the sediments it brings
-
attracting migratory species, especially in late spring
-
cleaning the river beds , particularly the spawning grounds
-
uprooting weed beds
-
dispersing the maximum turbidity zones
I.4 The strategies adopted
Unlike other river basins, where the nature of the relief allows large-scale management
works to yield valuable returns, the Dordogne basin does not lend itself to a policy centred on
the possibility of major undertakings. The basin’s characteristics have led to the development
of a programme based on a great number of different measures;
spread over the whole
territory, these have a cumulative effect in contributing to the overall reduction of flood risks
and to making life easier for the inhabitants when floods inevitably occur.
Prevention has to
concern the entire territory - but, logically, with particular emphasis on the zones facing the
largest challenges, so as to deal with the most critical situations. The measures adopted,
therefore, are not only efficacious locally but at the same time are relevant to the basin as a
whole.
In particular, they take into account the necessary interdependence between the
territories, both upstream and downstream of each other.
The five principal aims adopted
are:
1. to reinforce the forecasting and warning systems,
2. to lessen the flood risks,
3. to protect property and people,
4. to reduce vulnerability, and
5. to achieve better anticipating of floods thanks to collective organisation.
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(Carte)
Measures in the basin:
-
Better knowledge of the risks
Helping the elected bodies
Improving public awareness
More consultation
Implementing the action programme
Preserving the
wet zones
Getting the river bed and
banks back in order
Close watch on management
of the big hydroelectric dams
Protecting people
and property
Restoring the areas
for free flow
Reducing the
runoffs
Restoring the flood channels and
the areas for free flow of floods
Better warning system
Managing the dams
in alluvial plain
Map of the measures under the action programme currently under way