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abstract 839

MoGIRE, a Model for Integrated Water Management

Author(s): Arnaud Reynaud, Delphine Leenhardt
Research Fellows at INRA, France

Keyword(s): Integrated water management, River basin, Optimization, Scenarios

Article:

Poster:

Session: OS1k IWRM and water allocation

AbstractIntroduction

MoGIRE is a model for integrated water management at the river basin level,

allowing to optimise water use under several possible scenarios (agronomic, climatic or economic).

This model

is currently under development by an interdisciplinary team within the APPEAU project (2007-2010) funded by the

French National Research Agency within the “Agriculture and Sustainable Development” program. An application of

the model is proposed for the Neste system located in South-West of France.

Objective

The main

objective of the MoGIRE is to develop an interdisciplinary integrated framework based on mathematical

programming in order to evaluate scenarios for a better planning of agricultural and non-agricultural water use at the

river basin level.

Architecture of MoGIRE

MoGIRE may be viewed as a multi-use water allocation

model with an explicit representation of the water network at the river basin level.

Agricultural, urban

(domestic and industrial) and environmental water uses are represented in the model. Agricultural production

functions are derived from a biophysical models of crop growth, STICS (Brisson et al., 1998). The crop growth

model allows to characterize the relationships between agricultural water use and crop yields. Those relationships are

used as inputs in a regional agricultural production model that determines the optimal allocation of land among

possible crops and the resulting agricultural net profit. The urban water value is derived from econometric

estimations of water demands, see for instance Garcia and Reynaud (2004) for such a derivation in France.

MoGIRE then operates the network facilities and allocates water so as to maximise the river basin agricultural and

urban economic value from water use, under water delivery constraints resulting from the characteristics of the water

network and the minimum flow requirements. We make the distinction between two minimum flow levels: the Crisis

Minimum Flow (CMF) and the Target Minimum Flow (TMF). The CMF (in French, débit de crise) defines the

minimum flow under which biological life is not possible. When the water flow is lower than CMF, no irrigation is

allowed. The TMF (in French, débit objectif d’étiage) defines the water flow level above which biological life is not

constrained. When the water flow is greater than TMF, irrigation is not limited.

This pursuit of economic

objectives (aggregated social surplus resulting from water consumption in agricultural and non-agricultural regions) is

then limited only by water availability, water network characteristics, and minimum flow constraints.

Application of MoGIRE to the Neste sytem (France)

Within the APPEAU project, MoGIRE is

currently applied on the Neste system located in South-West of France. The Neste system is a system of rivers

artificially recharged by upstream reservoirs located in the Pyrenees mountain. This system has been chosen first

because it is managed by a single operator, the Compagnie d’Aménagement des Coteaux de Gascogne (CACG).

Second there are significant water scarcity issues in that area that make the development of an integrated water

management model relevant. For instance, the relationship between the CACG and farmers is defined by a contract.

This contract specifies first, a discharge rate and second, a quota associated to each unit of discharge rate (l/s)

subscribed by a farmer. Given the current price for the discharge rate, the demand of discharge rates by farmers

exceeds the flow capacity of the system. The CACG must then manage a waiting list for quota allocation

We

then plan to use MoGIRE in order to optimize and simulate various agronomic, climatic or economic scenarios on

the Neste system. For instance, a set of scenarios concerning various spatial distributions of cropping systems within

the Neste system chosen to reach a compromise between minimising the irrigation demand and maximising the farm

and the regional income is currently under development.

Reference List

Brisson, N., Mary, B.,

Ripoche, D., Jeuffroy, M. H., Ruget, F. e. al., 1998. "STICS : a generic model for the simulation of crops and their

water and nitrogen balances. Theory and parameterization applied to wheat and corn". Agronomie, 18: 311-

346.

Garcia, S. and A. Reynaud, 2004. "Estimating the benefits of efficient water pricing in France" , Resource

and Energy Economics, (26), 1-25.

Events

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Practical Infos

MoGIRE, a Model for Integrated Water Management