Conflict Resolution of Water Allocation in Polrud Irrigation System

Transcription

1 Conflict Resolution of Water Allocation in Polrud Irrigation System (An Approach to Multi-Criteria Decision Making) M. Zarghaami, M. Doroodian 2, A. Salavitabar 3 Abstract: Water is needed in all aspects of life and is vital to its social, economical and environmental dimensions. Having a key role in sustainable development, Water management requires an integrated approach. Several methods have been developed to integrate management in water supply planning. The rising of population in Iran puts significant pressure on authorities and infrastructures to provide water. Without improvement in water management, Irrigation demand will continue to increase, water supplies will diminish and the population pressure will decay infrastructure. Water shortage has included the development of innovative management and supply enhancement measures. A wide range of demand management and supply enhancement measures has been considered in dividing a management plan to increase supply system reliability, to respond to shortage events, and to delay the construction of new supply sources. Effective water management requires a comprehensive consideration of all related aspects, e.g., technical, social, environmental, institutional, political and financial. The conventional methods of cost-benefit analysis and singleobective models have changed to multi-obective models. For Polrud proect in the North of Iran, the most important aspects of operations is the regulation of water at the right time to the demand fields. The role of Polrud proect for reliable supply of water, improving rice and tea production, domestic water supply and reducing social conflicts is distinguished. This paper describes compromise programming to solve Multi-Criteria Decision Making in irrigation planning. Keywords: multi-criteria, decision making, social conflicts, irrigation planning, compromise programming, Iran. Introduction: Integrated water resources management (IWRM) has been gaining momentum in the last years. Being a truly interdisciplinary concept aiming to consider quality and quantity problems of both surface and groundwater simultaneously, IWRM requires the sustained cooperation of experts with different academic and technical background. To ensure a consistent approach towards IWRM, a decision making framework has to be Ph.D. candidate in Sharif University of Technology, Tehran, Iran, [email protected]. 2 Senior Engineer, Water Resources Section, Mahab Ghodss Consulting Engineers. 3 Manager of Water Resources Section, Mahab Ghodss Consulting Engineers, and P.B.: , Tehran, Iran. [email protected], Fax:

2 established considering the feedback and negotiating mechanisms involving the political leadership, the water resources management agency and the affected public. Amount of rice that imported for Iran, reached to.4 million of tons during 995 while domestic rice production has been.6 million of tons at the same time. It is expected that rice demand in Iran will reach to 3.5 million of tons by 2020 as the growth of population. So, if the country cannot succeed to produce enough rice (by Polrud and similar proects), the government should pay more to import rice in the future. Also it should be mentioned by implementation of Polrud dam, tea production will increase 85% due to change of irrigation system from present rain-fed to water-fed in proect future. There is one cropping season in a year April-August for cultivating rice, May to September for tea and a flood season during March to May which followed by a dry period June to August. Since expect in wet years there is sufficient water for irrigation, therefore in the normal and dry hydrological condition, part of the rice fields can not be irrigated. The amount of water shortages are substantial in some years and cause social problem. For this reason a dam is planned to be constructed on Polrud river to regulate water as well as control of flood hazard during winter and spring. Since the river carries substantial amount of sediment inflow, the reservoir will face significant volume of sediment deposition, which diminish the life of the reservoir. For this reason periodical impounding and flushing rule is set to diminish the sediment deposition in the reservoir. The study of system optimization is carried out to improve the system performance (regulate water for rice, tea, domestic water supply ) subect to all constraints. A simmilar work in urban water is for Jenkins & Lund (2000). Case Study: Case study was carried out on the Polrud river basin. The basin is located in northern part of Iran and south of Caspian Sea (Fig.). Fig. - Study Area Fig. - Region a etudier 2 - Dam Site 2- Polrud s Irrigation Area 3- Irrigation Area of Amlash and Biarpas Dam and irrigation proect of the Polrud river system, shown in Fig. covers an irrigating area of 2848 ha and lies between 36 o 54 to 37 o 3 N and between 50 o 5 and

3 50 o 34 E. It springs from Alborz ranges and flows toward Caspian Sea. Out of the ranges and irrigating lands downstream of the Polrud river, 7268 ha is suitable for rice crop and the rest 0880 ha is allocated for tea cultivitation. Polrud system has been divided into three subsystems, called ) Polrud (right and left side of Polrud river 2) Amlash irrigation area, 3) Biarpass irrigation area (both west part of Polrud system). The Polrud irrigation area receives its water demand directly from a diversion dam downstream Polrud reservoir. Amlash and Biarpass irrigation area take their water demand via a 35- kilometer transfer canal after utilization of their local water potential. monthly flow (MCM) Oct Nov Dec Jan Feb Mar Apr May Jun July Aug Sept Fig.2- Polrud s River Inflow to Dam Site Fig. 2- Debit entre dans le reseroir du barrage de Pol-Roud Purposes of the Proect: - Supply regulated flow for the present and developing rice field with respect to the land potential in the region. - Irrigation of present upland rain-fed tea cultivating area to increase tea production and its benefit. - Supply Amlash and Biarpass water deficit after utilization of their local unregulated water potential. - Supply 40 MCM/y potable water for the near town and villages. The land potentials include present irrigation land and also developing lands suitable for rice cultivation as well as present uplands rain-fed tea area. Now, there is about 3970 ha rice cultivation land irrigated by Polrud natural water potential with low guarantee level. 906 ha extra land exists which is suitable for development of rice field. The amount of the improved and developing area for both crops in the whole system is shown in Table (). 3

4 Table - Distribution of lands for rice and tea in the Polrud proect boundary Tableau - Distribution des terres du riz et du the dans le perimetre du proet de Pol-Roud District Crop Area (ha) Name Status Rice 3970 A Improvement Polrud Rice 906 A2 Development Tea (uplands) 7034 A32,A42 Development Rice 936 A6 Improvement Amlash Rice 48 A26 Development Tea (uplands) 40 A33,A43 Development Rice 945 A5 Improvement Biarpass Rice 363 A25 Development Tea (uplands) 2445 A34,A44 Development Schematic picture of system is described in figure 3: Inflow to Polrud Reservoir 484 MCM/Y 4 40 MCM/Y domestic water Q ha 206 (development) 69 Biarpass 2 3 Shalmanrud Samoush Under 00 m 4234 ha 856 Q=65 MCM/Y Under 50 m Under 200 m Q6 Q5 5 Q=662 MCM/Y Q2 Q2 Q7 945 (improvement) Q8 363 (development) Q + Q0 capacity= 20 cms (improvement) Shalman 936 (improvement) 906 (development) 48 (development) Q0 Q Reservoir Caspian Sea Tea( development ) Rice Transfer Cana l Fig. 3- Schematic View of Study Area Fig. 3- Vue schematique de la region a etudier Methodology: To utilize the regulated water, efficiently, certain issues such as the method of efficient distributing water among users, sharing patterns within different farms (tea and 4

5 rice) and the management of water in shortages must be planned. This study investigated integrated management such as environmental needs, distribution network optimization, new improved crops, and crop response to water (FAO- no.33), using a multi-criteria decision-making method. The obectives and criteria, which have been considered, include economic efficiency, area maximization and reducing risk of the water supply system. This system has three obectives: maximization of net benefit, equity between farmers and reliability. Although irrigating more area maximize the equity, but this may reduce the net benefit. To solve the problem of unemployment in the proect area, it would be social benefit to extend cultivating area may cause less economical benefits. The most sensitive period to water deficit for rice crop occurs in July. Linear obective functions and linear constraints of the irrigation system can be expressed mathematically as follows: Obective Functions:. Maximization of total net economic benefit MaxR m 4 n6 i A i B i C i Ai = Irrigation land of type i and Location i = Cultivating crop index (tea:-development, 2-improvement and for rice: 3-under 00 m and 4 for above 00 m in sea level) (refer to fig.3) = Location index (,2 for Polrud - 3,4 for Biarpass - 5,6 for Amlash) Ci = Cost of production of crop i per hectare Bi = Benefit of crop production per hectare of type I in the Location which relates to the price of crop and amount of production shown in table 2. Crop production is mainly depended on the water allocation per hectare. Table 2- Economical indices of cultivated crops in the Polrud proect Tableau 2- Les indices economiques de produits agricoles dans le proet de Pol-Roud Crop Rice (improvement) Rice (Development) Tea (Development) Price per kilogram (US cent) Max. Crop production kg/ha Cost of crop production per hectare (US$) Required water per hectare in July (m 3 ) Minimum water demand for crop production (%) Based on the criteria given in FAO 33, the relationship between rice and tea production and the amount of water deficit has been shown in Fig.4: Cost of preparing tea in the above of 00 meter in level is higher ( 3% ) and this is included for area A4 5

6 00 percent of decrease in production y = 0.02x x Rice Tea y = x percent of water shortage Fig. 4- Yield Response to Water (Doorenbos and Kassam, 979) Fig. 4- Rendement de produit par rapport a l eau mise a sa disposition 2. Maximization of irrigation land (A): MaxA m 4 n6 A i i MaxA.08( A A A A A A ) A A A A A ) ( A44.08 is the employment opportunities of rice crop which is evaluated 8% more than tea crop. Where A A 2 is rice cultivation zone, A 3 A 4 is tea cultivation zone. 3. Minimization of risk (maximization of reliability) Regulated discharge in July is about 57.7 mcm at Polrud diversion dam, 6.4 mcm at Shalman rud and 3.7 mcm at Biarpass. So, the following linear equations as constraints of the reliability of irrigation system can be considered: At Polrud diversion dam: Q Q Q Q Q 57.7 * Risk At Shalmanrud diversion dam : Q Q Q Q Q Q Q Q ( ) * Risk At the Shalmanrud basin area : Q Q 6.4* Risk 4 3 At the Biarpass basin area : in the mean 6

7 Q Q 3.7 * Risk 6 7 Constraints. Water allocation constraints for each area (for example): Q A X A 2X 2 2. Where X i is the water demand constraints for each area: X min, i X i X max, i 3. Land constraints: A min, i A i A max, i 4. Environmental Release: Based on the environmental evaluation, for example the minimum release has been considered 4.6 mcm in July for Polrud and Shalmanrud rivers. Q Q Capacity of water transfer canal: Q 2 Q7 Q Multi-criteria decision-making with compromise planning method: In this study for modeling various criteria the Compromise Programming (Zeleny, 973) is used. Compromise programming and composite programming are based on scaling of the outcome for each criterion and subsequently minimizing the distance from the goal point. The distance in the compromise programming is the family of: * f f w w p Mininimizing : L Components of the ideal point Worst outcome of obective i Weights for obective i Parameter defining the metric of p m w L p W is the weight while p expresses how strong distances from the ideal point are emphasized. p= corresponds to simple average; in the case of p=2 a simple squared distance is calculated while in the case of p= infinite only the largest deviation is considered. Many works have been done by this methodology (Simonovic 989, Szidarovsky et al. 986, Abrishamchi &Tarishi 997). Like implementations in urban water can be find (Zarghaami, 200). p f * f f ( x) f w * p p L p 7

8 Table 3- weights, idealistic and worst values of each criterion Tableau 3- Les poids, les valeurs ideales et critiques (non souhtable pour chaque critique) Samples of normalized idealistic worst value Criterion relative weight w value f of f w 2 3. Benefit (0 6 $) Land (ha) Risk The analysis of results: Since the functions of obective and benefit are non-linear, therefore the model is also non-linear. After execution of the model with the GAMS software the following results obtained: A- For the different sets of weight in the tables 4, the optimum irrigation s area is given: Table 4-Results of Multi-criteria Optimization (different sets of weights for criteria) Tableau 4- Les resultats d amelioration de Multi-variable (ensemble de differentes valeurs pour les criteriums) 4() RISK Revenue Area Weight Optimum Value Unit million $ ha * 4(2) RISK Revenue Area Weight 8 Optimum Value Unit million $ ha 4(3) RISK Revenue Area Weight Optimum Value Unit million $ ha 4(4) RISK Revenue Area Weight 8 Optimum Value Unit million $ ha 4(5) RISK Revenue Area Weight Optimum Value Unit million $ ha - If decision-maker emphasis on the Risk, the benefit will be reduced, 4(). Brooke et al. (998) 8

9 2- If he/she put too much emphasis on the Area the Risk of irrigation will be increased, 4(2). 3- If only the benefit is considered, 4(4), in spite of achieving the total benefit from the irrigation (equal the values of simulation approach: US $ 7.2 and total irrigation equal to ha), but the level of risk is undesirable. 4- This risk doesn t be emerged in the economical analysis with (B-C). In this study this deficiency is eliminated with the help of FAO graphs. B- In the figure 5 by detailing table 4(), the recommended area is presented: 4() RISK Revenue Area Weight Optimum Value Unit million $ ha 6000 Hectar Optimum Feasible A A2 A32 A42 A33 A43 A34 A44 A5 A25 A6 A26 Farms Fig. 5- One of the results and recommended areas for irrigation in described weights Fig. 5- L un des resultats recommande pour l irrigation avec un group a valeur fixee From the analysis of the results of recommended area for other tables this results is cleared: - Since the tea cultivation is beneficial, in spite of the increase in pumping cost for the higher elevation, the irrigation for the tea is recommended in spite of the reduction in the development rice irrigation. 2- The development rice field was not recommended unless in the case which maor emphases is on land development. For this increase we must be forced to reduce the improvement of customary rice field or tea which result to be far from optimum solution. 3- For the improvement rice field, the improvement of minimum area (3970 ha. Rice field based on the previous year s cultivation) should be considered. The improvements of the existing rice fields are not optimum. rather the development of yield response to water, FAO 33, (the efficiency of rice production vs. water supply) 9

10 tea fields is more beneficial. This result obtained from sensitivity analysis of weights of criteria. 4- The advantage of this model is the optimum decision for the value of irrigation in the unit area (in July). For the case of improvement rice the optimum point is supply 85% to 90% of water demand (i.e. 39m 3 /ha.). But for the development rice field, the solution of the model impress on the maximum deficit as much as possible. Since water in the tea field gives a more benefit, the 00% supply of water (i.e. 843 m 3 /ha.) for tea is optimum when the benefit criteria is emphasized. In the case that the risk is important or the increase of irrigation land, then the supply of water for tea should be minimized. 5- In wet years, water supply is recommended first for development rice field and then improvement rice field. C- The figure 5 is drawn in the case of p=2. p is the sensitivity of the distance from the desired point for the decision-maker for each criterion. With the increase of P from to 20, the risk value is reduced and consequently the irrigation area and total income is reduced. D- The rate of water in the canal is 4.8 MCM in July. Compare of this figure to the capacity of 53.6 MCM for canal is significant. For further studies the optimum capacity of canal can be calculated as a decision variable. Validation of Results: these results are based on the execution of the described mathematical model. The GAMS software does the execution of the model. The GAMS software has been used for various national and international proects, as World Bank proects. We used Conopt2 as a solver of Windows based GAMS. Conclusion: This integrated management shows reflective approach than simulation and B-C (one-obective) studies. Best implementation of decision-maker utility is other important result. The results obtained revealed that the method is capable of being employed by decision-makers in their comprehensive water management studies. References: [] Abrishamchi, A., Tarishi, M Multi-criteria Decision Making in Irrigation Planning, 4 th international conference on civil engineering, Sharif university of technology: Tehran, Iran. [2] Brooke, A., et al GAMS: General Algebraic Modeling System. GAMS Development Corporation: Washington DC. [3] Zarghaami, M Multi-Criteria Decision Making in Water Supply and Demand Management, (M. S. Thesis), Institute of Research On Planning and Development: Tehran. [4] Zeleny, M Compromise Programming, Multiple Criteria Decision-Making. Cochrane, J.l. and M.Zeleny (eds.), University of South Carolina Press: Columbia. [5] Doorenbos,. and A. H. Kassam Yield Response to Water, FAO Irrigation and Drainage, paper No. 33, Food and Agriculture Organization: Rome. [6] Simonovic, S Application of Water Resources Systems Concept to the Formulation of A Water Master Plan, Water International, Vol.4, no., PP [7] Jenkins, M.W. and Lund, J.R Integrating yield and Shortage Management Under Multiple Uncertainties, ournal of Water Resources Planning and Management, ASCE, (in press). Brooke et al. (998) 0

11 Re solution de Conflit Concernant L appropriation de L eau Dans le Systeme D irrigation de Polroud (Procede de prise de decision de Multi-Criterium) Resume: L eau est une matiere necessaire et elle est au point de vue de l aspect social, economique, et environemental, tres vitale. Prenant compte de son role de cle dans le developpement stable, la gestion des ressources d eau, a besoin d une methode de gestion integree. Pour la gestion integree dans la planification de l alimentation d eau, plusieurs procedes sont accomplis. Augmentation de la population en Iran, exerce une pression evidente sur les administrateur et sur les organes a propos de l alimentation en eau. Sans amelioration de l affaire de la gestoion des ressource en eau, les besoins en eau d irrigation sera augmente touours de la meme maniere. L alimentation en eau sera diminuee et pression du peuple entrainra la diminution du rendement du systeme de la gestion des ressources en eau. Le deficit d eau, entraine le developpement de la gestion des ressources en eau dans le sens des procedes de l alimentation d eau et ainsi que la gestion de consomation. Gestion correcte de planification avec le but d augmenter la capacite de confiance du systeme d alimentation en eau a repondu a la diminution des deficits, economie sur l affectation de budet aux proets de developpement des resources en eau. La gestion efficace des ressources en eau necessite de prendre en compte de facon general, toutes les affaires en relation entre eux, au point de vue technique, social, environemental, d organisation, politique et finencier. Les procedes traditionnels (Benefice-frais) dans la plupart des modeles, sont trasformes en modele multi-criterium par une fonction de but. Dans le proet de pol-roud au nord d Iran, le probleme le plus important est l exploitation de l eau regularisee dans le temps fixe pour les usages d irrigation. De meme le role du proet de Pol-Roud pour alimentation en eau rassuree, amelioration du bilan du riz et du the, l alimentation d eau urbaine et diminution des tension sociales est evidente. Dans cet article, il sera explique le procede de plainfication d accord pour resoudre le modele de prise de decision de multi-criterium. Key Word: Prise de decision de multi-criterium, tension, Sociale, planification d irrigation, Planification d accord.