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<br />,,,t'\'
<br />
<br />inputs and inputs are employed in fixed propor-
<br />tions. Also, water use, employment, and residuals
<br />discharge are assumed to vary linearly with output.
<br />The linearity inherent to input-output analysis is
<br />not particularly troublesome in the absence of
<br />relatively large expected or predicted changes in
<br />the output of anyone sector. However, the
<br />technology used by energy.related sectors undergo-
<br />ing relatively large expansion may be expected to
<br />be substantially different from that currently used.
<br />Moreover, coal-resource development in the
<br />Yampa River basin may result in new types of in-
<br />dustry coming into the region.
<br />The input-output model of the Yampa River
<br />basin economy was designed to consider
<br />technological differences between the existing and
<br />potential new coal-mining. thermal-electric
<br />powerplant, and unit-train operations, and to con-
<br />sider the possibility that a coal-slurry pipeline
<br />and/or coal-gasification plants might be operated
<br />in the region. Three sectors were included in the
<br />model to represent expansion of surface mining of
<br />coal. underground mining of coal, and unit-train
<br />operations. An additional three sectors were in-
<br />cluded to represent (potential) thermal-electric
<br />powerplants, coal-gasification plants, and a coal-
<br />slurry pipeline.
<br />Plant-process models (I. C. James II, E. D. At-
<br />tanasi, T, Maddock III, S. H. Chiang, B. T. Bower.
<br />and N. C. Matalas, written commun.. 1978) were
<br />used to derive estimates of the direct production-
<br />requirement coefficients for the new and expansion
<br />sectors. These coefficients give the inputs directly
<br />required by the new and expansion aectors, per dol-
<br />lar of output. from all other sectors of the regional
<br />economy.
<br />To provide estimates of water withdrawal in the
<br />Yampa River basin under several energy-
<br />development alternatives, it waa necessary to
<br />derive estimates of water withdrawal per dollar of
<br />output for each sector of the economy. For most of
<br />the existing sectors (32 and 45 in table 2), water-
<br />withdrawal coefficients were derived by estimating
<br />the total quantity of water withdrawn by each of
<br />the sectors in 1975, and dividing this total by the
<br />dollar value of the output of the corresponding sec-
<br />tor during that year. Water-withdrawal coefficients
<br />for the new and expansion sectors were primarily
<br />derived using plant-process models (I. C. James II,
<br />E. D. Attanasi, T. Maddock III. S. H, Chiang. B.
<br />T. Bower, and N. C. Matalas, written commun.,
<br />1978; Hirsch, 1979). New electric powerplants were
<br />assumed to use wet-cooling towers. Estimates of
<br />
<br />water-withdrawal coefficients and of the quantity
<br />of water withdrawn by each sector in 1975 are
<br />presented in table 2.
<br />Also presented in table 2 are the water-
<br />withdrawal multipliers as estimated using the
<br />input-output model. Whereas the water-with-
<br />drawal coefficient for a sector is an estimate of the
<br />direct water-withdrawal per dollar of output, the
<br />water-withdrawal multiplier is an estimate of the
<br />total (direct and indirect) water withdrawal by all
<br />sectors of the regional economy per dollar of output
<br />delivered to final demand (that is, ultimately con-
<br />sumed in or exported from the basin) by the sector
<br />in question. For example, if a new thermal-electric
<br />powerplant (sector 35) is to generate one dollar's
<br />worth of electricity for export from the basin, it will
<br />directly require that about 99 gallons (375 L) of
<br />water be withdrawn, But. it is estimated that due
<br />to indirect effects (including increased mining of
<br />coal to fuel the powerplant) the export of the dol-
<br />lar's worth of electricity will directly and indirectly
<br />result in the withdrawal of a total of about 118 gal-
<br />lons (447 L) of water.
<br />Though not presented here, estimates of the
<br />water-consumption coefficients also were derived,
<br />along with estimates of the water-consumption
<br />multipliers and total water consumption in the
<br />basin in 1975. These estimates are presented in
<br />Hirsch. James. and Schefter (1978, table 5).
<br />It is estimated that the livestock sector in 1975
<br />withdrew and consumed. by far. the most water
<br />-primarily for the irrigation of pastures and
<br />hayfields, But the existing electric-energy (27) and
<br />surface coal-mining (6) sectors were estimated to
<br />rank second and fourth, respectively. in the quan-
<br />tity of water withdrawn in the basin in 1975
<br />(table 2).
<br />Estimates were derived of the quantity of 13
<br />types of residuals discharged per dollar of output
<br />by various sectors. For the energy-related sectors,
<br />these residuals coefficients were derived primarily
<br />using plant-process models (I. C. James II, E. D.
<br />Attanasi, T. Maddock III. S. H. Chiang. B. T.
<br />Bower, and N. C. Matalas, written commun.,
<br />1978). The residuals coefficients for the expanded
<br />surface-mining sector were derived under the as-
<br />sumption that the coal would be mined under a
<br />moderate to high level of land reclamation to
<br />reduce wind- and water-borne sediment (I. C.
<br />James II, E. D. Attanasi, T. Maddock III, S. H.
<br />Chiang, B. T. Bower, and N. C. Matalas. written
<br />commun., 1978). For other sectors, the estimates of
<br />
<br />15
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