Cost-Benefit Analysis of Artificial Recharge

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A PRESENTATION On COST-BENEFIT ANALYSIS OF ARTIFICIAL RECHARGE PREPARED BY KODINARIYA ANKIT MULJIBHAI Of M.TECH. (Sem. III), WATER RESOURCES ENGINEERING. (Roll No.: P10WR330) GUIDED BY: Dr. B.K.Samtani Prof. B.J. Batliwala DEPARTMENT OF CIVIL ENGINEERING SARDAR VALLABHBHAI NATIONAL INSTTITUTE OF TECHNOLOGY SURAT- 395 007, GUJARAT 2011-2012

INTRODUCTION : 

INTRODUCTION In countries with limited water resources, comprehensive and rational water resources development is a necessary condition for optimum social and economic growth. Here we understood definition of cost and benefit and how it is associated with the project. Here one case study is taken for Las Vegas.

What is Benefit and Cost? : 

What is Benefit and Cost? Benefits from a water resources project can be classified into three categories: Direct benefits refer to those that are produced on account of direct physical effects of projects, such as increased agricultural production, hydro-power generation Benefits arising out of technological and economic linkages of the effects of a project are regarded as indirect, e.g., increase in agricultural productivity on account of flood control measures. Intangible benefits include the values of positive outcomes regarded as reductions in health risk, pain, and suffering, e.g., which cannot be estimated from market data.

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Cost for a water resources project can be classified into following categories: Actual costs are the costs which the firm incurs while producing or acquiring a good or a service like the cost on raw material, labor, rent, interest, etc. Alternative costs are the return from the second-best use of the firms resources which the firm forgoes in order to avail of the return from the best use of the resources. Sunk costs are the costs that are not altered by a change in quantity and cannot be recovered; e.g., depreciation. Incremental costs are the additions to costs resulting from a change in the nature and level of business activity, e.g., change in product line or output level, adding or replacing a machine, changing distribution channels, etc.

Cost-Benefit Analysis : 

Cost-Benefit Analysis Benefit – Cost Analysis is a systematic quantitative method of assessing the desirability of government projects or policies when it is important to take a long view of future effects (1) Both costs and benefits of a project must be measured and expressed in commensurable units (2) It is the main analytical tool used to evaluate water resource and environmental decisions (3) Benefits of an alternative are estimated and compared with the total costs that society would bear if that action were undertaken (4) Viewpoint is important - some groups are only concerned with benefits, others are concerned only with costs

Decision Criteria : 

Decision Criteria Economic comparisons of projects are most commonly made on the basis of Net benefits: the optimum scale of development for a given project occurs at the point where its net benefits are at a maximum. Net benefits are at a maximum when the benefits added by the last increment of a project are equal to the cost of adding that increment. Benefit/cost (B/C) ratio: Benefits and costs can be expressed as a ratio by dividing discounted benefits by discounted costs. A project is economically justified if its B/C ratio is greater than 1.00. Internal rate of return (IRR): This criterion computes the rate of return, or discount rate, which just equates discounted benefits with discounted costs. If the computed rate of return is greater than a specified discount rate, then the project is determined to be economically justified.

ARTIFICIAL GROUND WATER RECHARGE : 

ARTIFICIAL GROUND WATER RECHARGE Utilization of holding basins: Water is recharged by releasing it into basins formed by construction of dikes or levees or by excavation. (2) Flooding: This method can be used where topography is relatively flat so the flood can be spread over a large area. (3) Stream channel: In this method, channels are modified to enhance the infiltration process. For this purpose, the time and area over which water is recharged should be increased. (4) Recharge well: Recharge wells draw water from the surface to aquifers. Well recharging is practical where deep confined aquifers must be recharged or where economy of space, such as in urban areas, is an important consideration. (5) Furrow: Water is distributed to a series of furrows. The furrows are usually shallow, flat bottomed, and closely spaced to provide maximum water contact area.

CASE STUDY OF COST-BENEFIT ANALYSIS OF ARTIFICIAL RECHARGE IN LAS VEGAS VALLEY, NEVADA : 

CASE STUDY OF COST-BENEFIT ANALYSIS OF ARTIFICIAL RECHARGE IN LAS VEGAS VALLEY, NEVADA Location of Las Vegas Valley and area of interest

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Total groundwater pumpage in Las Vegas Valley, by type of pumper,1956–1998 CNLV = Cities of Henderson North Las Vegas LVVWD = Las Vegas Valley Water District NAFB = Nellis U. S. Airforce Base

Artificial Recharge Process : 

Artificial Recharge Process Artificial recharge in Las Vegas Valley is accomplished by taking potable Colorado River water from the treatment plant through the existing distribution facilities in the lower demand months (October–April) and injecting it into the groundwater system through wells. The area of interest and focus of this study is the northwest part of the valley. Because the aquifer system is confined, this benefit will directly accrue to all pumpers in the valley by lowering pumping costs, reducing well deepening and re-drilling costs, and providing the indirect benefit of slowing and perhaps halting land subsidence.

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Amount of water artificially recharged, 1987–1999, in Las Vegas Valley

Cost-Benefit Assumptions : 

Cost-Benefit Assumptions it is assumed that the stakeholders are those who pump groundwater and they are made up of municipal purveyors, domestic single-family units relying on a single well, and commercial pumpers. The number and type of wells and the average depth drilled by decade are shown in Fig.A the only alternative project is a no action alternative, where artificial recharge does not take place. This alternative is undesirable because it decreases the available water resources and greatly reduces the flexibility of water resource management. (3) all costs and benefits are based on fiscal years (FY) 1996-1998.The costs of most of the items evaluated are calculated for FY 1996 and 1997. Some costs, such as for well drilling, are for 1998, but these are nearly the same as for FYs 1996 and 1997. (4) The yearly water use amount for a typical domestic well owner is estimated to be about 1,230 m3. All well owner and GMP costs and benefits are based on this unit price per user of dollars/1,230 m3/year.

Cost of Water : 

Cost of Water The total cost of artificial recharge through existing facilities is listed in above Table The estimated annual costs for a well owner to operate a well with GMP and accompanying artificial recharge or without GMP and no artificial recharge are listed in above Table

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Domestic Well Owner’s Costs to use Groundwater In both cases, construction costs for new wells are the same, but rehabilitation costs are much higher if groundwater levels continue to decline, as is likely in the northern part of the valley. Some wells may never fail or go dry depending on site characteristics, but some wells will fail in a few years due to a variety of reasons, even with artificial recharge.

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Number and average depths of deepened and replaced wells by decade, in area of interest The costs for non-municipal well owners to connect to the LVVWD’s facilities are listed in Following Table Fig. A

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Following Table summarizes the relative benefits of artificial recharge to an individual groundwater pumper and the relative costs to the GMP.

CONCLUSION : 

CONCLUSION CBA represents important economic work because water projects are a well-touted mechanism of relieving water scarcity. Political pressure favoring water projects can be enormous due in part to the relative distribution of benefits to costs. Such pressure is not relevant to how economic analysis is conducted, but it is a key reason why analysis is conducted. Artificial groundwater recharge is an excellent water-resources management tool and provides numerous direct and indirect benefits not only to all groundwater pumpers, but to all water users in any region. Case study of Las Vegas Valley indicates that the benefits of artificial recharge are greater than the costs and there is a net savings of about $700 per year over a 20-year period for non-municipal members of the GMP that continue to use groundwater.

REFERENCES : 

REFERENCES 1.Batie Sandra S, Kramer Randall A, Edward Cox William (1989), Economic and legal analysis of strategies for managing agricultural pollution of ground water, Blacksburg, Virginia 2.Donovan David J., Katzer Terry, Kay Brothers, Cole Erin, and Johnson Michael (2002). Cost-Benefit Analysis of Artificial Recharge in Las Vegas Valley, Nevada , Journal of Water Resources Planning And Management. 3.Reichard Eric G., Bredehoeft John D. (2007), An Engineering Economic Analysis of a Program For Artificial Ground Water Recharge, JAWRA, Volume 20, Issue 6, pages 929–939, 4.Shahbaz Khan, Tariq Rana, Hanjra Munir A. and Robinson David (2011), Decision support model for water policy in the presence of water-logging and salinity, Water Policy Vol 13 No 2 pp 187–207 5.Jain S.K. and Singh V.P. (2003), Water Resources Systems Planning And Management, 1st Edition, Antony Rowe Ltd, Eastbourne, pg. 363-365. 6.Karamouz Mohammad Szidarovszky Ferenc ZahraieBanafsheh (2003), Water Resources Systems Analysis, CRC Press LLC, pg. 117-119