Answer to 2012 Social Benefit Cost Analysis: Dam Project
The study
This report studies social preferability of the dam proposal which aims at an extension of crop yields in the dry-farming area by introducing the irrigation system, including a branch with or without concerning an environmental impact, and then investigates a variation of social influence of the options under certain assumptions which change within a reasonable range. The study is based on basic methods of Benefit Cost Analysis from evaluating each scenario with their Net Present Values to testing sensitivities of the options against considerable fluctuation of crop prices and yields due to market and weather risks. The investigation proceeds in the following order; introducing each option and their expected impacts, identifying and evaluating costs and benefits, calculating net benefits at the present value, sensitivity tests, and conclusions as a final recommendation for decision makers.
The options and their likely impacts
Option 1 - The Base Case
Under this option without the irrigation scheme, farms will continue conventional dry-land farming, which earns a hundred dollars per hectare annually without any further costs. River downstream from the dam will remain available and provide with fishing and recreation services at a value estimated with the Travel Cost Method. These values are counted as the opportunity costs in the following options of the dam construction. In addition, downstream wetlands which would be damaged if the dam is constructed will be preserved with their associated natural ecosystem.
Option 2 - Dam Construction Without the Environmental Flow for Wetlands
This option allows the irrigation system installed into the participant farms so that the farmers can achieve higher crop yields as a primary purpose of this project although it will cost much not only for the water authority and the farmers but also for the surrounding natural environment and other economic activities. On the other hand, the dam project is expected to have a couple of positive side-effects such as flood protection and fishing and recreation services. These benefits and costs as a whole, in the form of the Net Present Value, applied a few typical discount rates, are to be assessed in comparison with the base case.
Option 3 - Dam Construction With the Environmental Flow for Wetlands
Finally, the case with the environmental water flow for wetlands is to be examined in order to estimate an minimum required value of their environmental services to implement the dam project. Under this case, less water is available for irrigation and that will cause crop yields decreased and so benefits from irrigated farmlands reduced; also, some costs just like annual water charges for the farmers will be saved as well. Thus, it is necessary to calculate changes in Net Present Values under the discount rates and estimate an annual required value of the wetlands.
The costs
Costs for Option 2 and 3, the dam construction with-without the environmental flow for wetlands, are classified on Table 1 into primary or secondary columns and priced or unpriced columns. The primary costs basically consist of those for the dam construction and maintenance and fixed and variable expenditures for the farmers to start and manage irrigation farming. The secondary costs come from a wide range of economy of the country from an economic impact on farmers in other regions with poorer cost-competitive farming to a few environmental damages in the surrounding areas like Algal Blooms and salinity effects.
Labor costs
A treatment of labour costs needs to be paid a special attention because unemployment exists in the case of the dam proposal. If the unemployed are entitled to gain some unemployment benefits, those payments are considered as transfer payments in the Benefit-Cost Analysis.
In this case, a half of the labour employed to construct the dam are currently unemployed and will get the wage equal to the unemployment benefit which are assumed to be 25 per cent of the market wage rate as shown in Table 2. The unemployment benefit, a typical example of transfer payments, is excluded in the analysis because money is transferred from the government to the unemployed without any goods or resources being traded in exchange. Therefore, the real cost arises in employing this kind of labor, otherwise the unemployed makes no opportunity cost by remaining jobless.
Contrarily, the rest half of the employed labor for the dam construction are currently employed in other industries of the country, if assuming no wage inflation in the labor market by implementing the dam proposal, with being paid the same wage as the dam construction. In other words, even if the dam proposal is not taken place, this labor is supposed to cost the same wage in other parts of economy; thus, the cost for the currently employed labor is not counted in this analysis.
Income tax
Extra income tax on the farmers in the irrigation district would be regarded as a transfer payment for the same reason mentioned in the discussion of labor costs. Unless making any differences in the quantity of inputs or outputs in the market, taxes and subsidies are basically excluded from calculation.
Table 1: A classification of costs
Primary
|
Secondary
|
||
Priced
|
Priced
|
Unpriced
|
|
Capital costs to construct the dam
Annual operation cost
|
Cost of converting farm land and the associated on-farm capital costs
|
The crop yield reduction elsewhere in the country
|
Salinity effects on the surrounding dry-land farmland
|
Cost of water for operating the irrigation system
|
Farm variable and overhead costs each year
|
Additional cost for Algal Blooms
|
|
Cost of water for the initial water storage
|
Annual water charges for the farmers
|
||
Costs of labor currently employed and unemployed
|
Opportunity costs of earning from dry-land farming
|
Table 2: Annual labor cost for the construction of the dam
Wage for labors currently employed
|
Wage for labors currently unemployed
|
Annual labor cost
|
Annual labor cost (real cost)
|
$2,500,000/yr
|
$625,000/yr
|
$3,125,000
|
$625,000
|
The benefits
A main benefit from the dam project is extended crop yields in the irrigation district to an annual value of twenty four hundred dollars per irrigated hectare (see Table 4). Moreover, a variety of secondary benefits will appears in upstream or downstream industries from the crop production and also arise as intangible effects in the surrounding environments of the dam (see Table 3). For example, secondary industries located in downstream of the value chain of the extra crop production, such as flour millers and bakers if the crop is grain, will experience a competitive market amongst competing other traders to obtain the extra product; the similar phenomenon will take place in upstream industries, namely between farmers and input suppliers.
Table 3: A classification of benefits
Primary
|
Secondary
|
||
Priced
|
Unpriced
|
Priced
|
Unpriced
|
Earning form the irrigated crop yield
|
Salvage value of the initial capital investment in the dam
|
Additional value of the farmer’s extra crop products
|
Flood protection service of the dam
|
Salvage value of the initial capital investment in the on-farm irrigation system
|
Additional value of the processor’s extra products
|
Fishing, water sports and recreation services of the dam instead of the river
|
|
Extra fertilizers sales of input suppliers in the irrigation district
|
Fish catches for commercial fishers
|
||
Extra fuel and chemical sales in the irrigation district
|
Table 4: Annual benefits from irrigated farmlands
Yield
|
Price
|
Land
|
Annual benefit per hectare
|
Annual benefit as a whole
|
4t/ha/yr
|
$600/t
|
50,000ha
|
$2,400
|
$120,000,000
|
Secondary benefits
In a competitive market, there are no secondary benefits (and costs,) so none should be included in calculation. For instance, given an extra amount of wheat available for flour millers, a flour miller will have to include any extra profit from grain processing in his payments for the wheat. Otherwise competing millers will bid higher and obtain the wheat. So the miller will have no true increase in net income.
The competition in the output market causes processors and retailers of the extra crop product to bid higher for it, by adding four hundred dollars per ton and a hundred dollars per ton respectively, in order to obtain it. In the analysis, added values in price as a result of competition are omitted from calculation of the Net Present Value as two items corresponding to these values in Table 4 are lined with strikethrough.
Opposite to the former case, additional revenues of input suppliers from extra fertilizers, fuel, and chemical sales (underlined in Table 4) should be considered as substantial benefits because farm variable and overhead costs include expenditures for extra usage of them.
Calculating net benefit
Option 2 - Dam Construction Without the Environmental Flow for Wetlands
In the case of Option 2, the Net Present Value shows negative figures, and the Benefit Cost Ratio is less than one, under any discount rates not less than 7 per cent, which means the total discounted cost exceed the total discounted benefit if the social rate of time preference or the market rate of inflation in the country is at least 7 per cent. Table 5 also indicates that the Internal Rate of Return, defined as the rate at which the sum of all discounted benefits and costs is zero, is equal to 6.03%.
Table 5: Net Benefit of Option 2 under three different discount rates
Discount rate
|
5%
|
6%
|
7%
|
NPV
|
$60,027,520
|
$1,285,680
|
-$43,882,142
|
BCR
|
1.03
|
1.00
|
0.970
|
IRR
|
6.03%
|
Option 3 - Dam Construction With the Environmental Flow for Wetlands
Under Option 3, all NPV figures corresponding to the same discount rates in Option 2 mark considerable amount of loss in the society, as a result of the reduction in benefit exceeding the save in cost from the the decreased irrigated farmland (see Table 6). In order to compensate such loss in the economy, the environmental services of the wetlands are required to have a minimum value per annum under each discount rate. These values are assumed to arise at the start of year 4 after the dam construction is finished and continue until the end of the project.
Table 6: Net Benefit of Option 3 under three different discount rates
Discount rate
|
5%
|
6%
|
7%
|
NPV
|
-$164,467,310
|
-$188,612,211
|
-$206,190,255
|
BCR
|
0.904
|
0.875
|
0.846
|
Minimum value of the wetland per annum
|
$11,095,665
|
$14,929,930
|
$18,946,703
|
The treatment of uncertainty
Price fluctuation
Fluctuation of commodity prices in the world market frequently takes place due to unpredictable market factors, e.g., good harvests in other countries. Assuming that the world market price for the crop faces the change either by 10 per cent more or less every 5 years (the first one occurs in year 8) from the case of Option 2, the Net Present Values show variations from the case without fluctuation, so the Internal Rate of Return slightly shifts (see Table 7 and 8). Consequently, normal changes in the world commodity prices, a maximum margin of 10 per cent plus or minus, does not seem to affect the dam project significantly.
Table 7: Net Benefit under three different discount rates while the price for the irrigated crop decreases by 10 % every 5 years
Discount rate
|
5%
|
6%
|
7%
|
NPV
|
$27,837,177
|
-$25,607,247
|
-$66,590,832
|
BCR
|
1.02
|
0.984
|
0.954
|
IRR
|
5.49%
|
Table 8: Net Benefit under three different discount rates while the price for the irrigated crop increases by 10 % every 5 years
Discount rate
|
5%
|
6%
|
7%
|
NPV
|
$92,217,864
|
$28,178,608
|
-$21,173,453
|
BCR
|
1.05
|
1.02
|
0.985
|
IRR
|
6.54%
|
Drought
Another risk that farmers and other relevant subjects of the project are likely to face is drought. Let the analysis suppose that the irrigation district experiences a drought every 10 years (the first one occurs in year 13,) and the whole water flows for irrigation is unavailable in the drought years; the farmers in the district have to temporarily go back to dry-land farming in those years, but any relevant costs to irrigation does not exist. Compared to the result of the case with price fluctuation, effects of the droughts on the project seem considerably influential; the Internal Rate of Return falls more than one per cent (see Table 9).
Table 9: Net Benefit under three different discount rates while a drought prevent farmers from irrigation every 10 years
Discount rate
|
4%
|
5%
|
6%
|
NPV
|
$41,431,034
|
-$16,926,545
|
-$61,301,244
|
BCR
|
1.02
|
0.990
|
0.961
|
IRR
|
4.68%
|
Conclusions
First, the study demonstrated that Option 2, the dam construction with the environmental flow for wetlands, is beneficial under a certain range of discount rate; however, even if so, returns from the project which the society will gain are not huge as the Benefit Cost Ratio shows under conventional discount rates.
Second, under Option 3 which preserves the wetlands at an expense of a portion of water for irrigated farming, the value of the wetlands is required to hold at least some million dollars per annum to implement the project, though the exact value depends on the applied discount rate.
Finally, the dam project does not seem significantly vulnerable to market and weather risks; if some risks against the crop production like price fluctuation and droughts are expected through the project term, it will be feasible to achieve the net social benefit at a positive figure.