The report of the International Garrison Diversion Study Board is bound in six volumes as follows: REPORT APPENDIX A - WATER QUALITY APPENDIX B - WATER QUANTITY APPENDIX C - BIOLOGY APPENDIX D - USES APPENDIX E - ENGINEERING APPENDIX D USES INTERNATIONAL JOINTCOMMISSION December 3, 1976 December 3, 1976 International Garrison Diversion StudyBoard Ottawa, Ontario, Canada Billings, Montana,United States Gentlemen: The Uses Committee is pleasedto submit herewith its final reportin accordance with the terms ofreference given to it by the International Garrison Diversione& Study Board. H.G. Mills, CanadianCo-chairman ,,I r " i / .I ,' . -,/'+.f?&&/p&<f T .A. Sandercock, Canafim Member United States Member & yjj 9-42. D.M. Tate, Cazadian Member E.W. Stevke,United States Member (ii) SUMMARY The Uses Committeehas analyzed the impacts of GDU onmajor water uses in the Red, Assiniboine and Souris river basins andon Lakes Winnipegand Manitoba. Water Uses includedin the analysis are: munici- pal,industrial, agricultural, rural domestic, recreational, fish and wildlife, andother. The analysisof GDU impacts is confined to usesin Canada.The effects upon theseimpacts of variousalternatives andmodi- ficationsto the authorized GDU project were alsoanalysed. The following sections summarize theresults of the Uses Committee'sanalysis. (a)Municipal Use (1) Increasedcosts of municipal water supplytreatment: Deteriorated water quality will require, as a minimum measure,that currentlyinstalled or planned water treatmentplants be operated at peakefficiency, producing the best quality of water ofwhich they are capable.This measure represents an increased cost of $59,000 annually. Constituentssuch as nitrates, sulfates andsodium would remain at post- GDU levels since reduction of theseparameters is beyond the capability ofcurrent treatment facilities. Post-GDU levels of theseconstituents couldhave adverse effects on human healthin certain instances. The costof restoring the quality of current water suppliesduring, the post-GDU period(i.e. the cost of treating all chemicalconstituents down tocurrent levels) will beabout $1,895,000 annually. However, many constituents wouldbe reduced tolower levels thancurrently experiencedthereby making overall quality of finished water supplies better.These increased costs would accrueto those communities in Manitobawhich draw part or all of their supplies from surface waters to beaffected by GDU; these are Emerson,Morris, St. Jean Baptiste, Souris, Portage la Prairie and Selkirk.If the treatment described above is adopted,the effects summarized in(a)(2), (a)(3), (a)(4) and(a)(5) would notoccur. Of thevarious alternatives or combinations of alterna- tivesinvestigated, some would slightlyreduce the treatment costs computed for GDU, others would resultin slight increases. Most (includingthe three combinations of alternatives) would notchange incrementaltreatment costs significantly. Combinations I1 and 111 would reduceannual costs of treating to current levels to about $1,848,000, a reductionof 2.5 percent. (2)Increased taste andodor problems at Souris and Portage la Prairie:This effect is attributableto the potential increases in biomass in theSouris and Assiniboinerivers due to increased nutrient loadings. Most ofthe alternatives and combinations studied would tend to increase the taste andodor problems predicted for the authorized plan. (3) Riskof methemoglobinemia in infants:Possible increases in nitrate levels in the Souris and Assiniboinerivers could increase therisks associated with this sometimes fatal disease. Mostof the alternatives andcombinations studied would tend to increase concerns regarding methemoglobinemia. (iii) (4) Problemsfor persons on salt-restricted diets: Water qualityprojections indicate that sodium levels on the Souris and Assiniboine rivers will increase as a result of GDU, causinghardship for personswith heart conditions and others on salt-restricted diets. Some of the alternatives studied would slightlyincrease these problems, others woulddecrease them. The combinationsstudied would generally decrease thesodium levels predictedfor the authorized plan. (5) Possiblelaxative effects: This problem is dueto predictedincreases in sulfate levels inthe Souris and Assiniboine rivers. Some ofthe alternatives studied would increasepotential problems of thisnature, others would decrease them.The combinationsstudied would generallyreduce concerns regarding laxative effects. (b)Industrial Use (1)Increased costs for treatment of industrial water supplies:Manitoba Hydro's installation at Selkirk would incuraddition- al treatmentcosts as a result of GDU. Incrementalannual costs of treating to required quality when best estimate conditions prevail in the Red River wouldbe $1600 during the peak impact period and $1100 during theequilibrium period. Achieving an acceptable quality of water when high estimate conditionsexist would resultin an annual incremental cost increaseof $93,500 (peakimpact) and $92,200 (equilibrium). All projected industrial uses requiring water low in TDS and free from taste andodors would incurincreased treatment costs as a result of GDU. None ofthe alternativesstudied would significantly affect industrial water treatment costs computed forthe authorized plan. Agricultural Use (1) Increasedleaching water requirementsfor some crops: A 10 percent increase in water applications wouldbe requiredto prevent yieldreductions in salt-sensitive crops such as carrots,beans and onionsin the Souris River Basin. None of the alternativesstudied would significantlyaffect this additional requirement. (2) Increasedflood damages along the Souris River: The additionof GDU returnflows to the Souris River would result in incrementalflood damages (direct plus indirect) of $24,000 annually. Most ofthe alternatives investigated wouldreduce these incremental damagessomewhat. The largestreduction, about 40 percent, would result from the combination of alternatives identified in this Appendix as Combination 111. (3) Potentialphysiological disorders in livestock: These effects wouldbe theresult of increased sulfate and nitrate levels and wouldbe most significant along the Souris River. Along theAssiniboine River, theseeffects wouldbe of less concern. No sucheffects are anticipatedalong the Red River. Some ofthe alternatives investigated would increaseconcerns in thisregard, others would decrease them. All ofthe combinations studied would reduce sulfate levels somewhat, while nitrate levels wouldbe increased. (4) Increased water suppliesfor irrigation: GDU return flows will increase potential supplies of water in the Souris and Red rivers.If the increased supply is firm, 5,200 acres of landin the Souris River Basincould be irrigated. Incremental flows in the Red Rivercould provide for the irrigation of 1,900 acres of land,although nodemand forthis water is anticipated. Most ofthe alternatives would reducepotential benefits to irrigation water supply. The largest reduction,about 2,700 acres in total, would result fromCombination 111. (d)Rural Domestic Use (1) Increased water treatmentcosts: Degraded water quality alongthe Assiniboine River will result in increased treatment costs to rural domestic users who dependupon the Assiniboine for their water supply. The costof treating to current quality (and for some parameters tolower than current levels) is estimatedto be $30,600 annually. None of the alternatives studied wouldhave a significant effect on increased treatmentcosts. (2) Problemsfor persons on salt-restricteddiets: These effects are similar tothose discussed in (a)(4) but apply only to the Assiniboine River. (3) Riskof methemoglobinemia ininfants: The effects describedin (a)(3) apply equally here with respect to the Assiniboine River. (4) Possiblelaxative effects: The effectsdescribed in (a)(5) are relevant here with respect to the Assiniboine River. (e)Recreational Use (1) Adverseeffects on quality of therecreational experience:Increased biomass and increased turbidity expected as a result of GDU couldadversly affect the quality of recreational experiencesalong impacted waterways. The alternativesconsidered, if implemented,would increase concerns in this regard. (2) Potentialbenefits to canoeing along the Souris River: Increasedstreamflow in the Souris River duringthe summer monthswould provideadditional canoeing opportunities provided that increased biomassdoesn't concurrently reduce activity. Most ofthe alternatives wouldreduce this potential benefit. Combination 111 would decrease any potential benefit byabout 50 percent. (f)Fish and Wildlife Uses (1) Loss of35,500 ducks and 2,700 hunter man-days: The loss of wet:Lands within the GDU project area will reduceannual duck populationsin Manitoba by 35,500ducks, or about 2 percentof the annual population.This loss would inturn result in an annual loss of2,700 hunter man-daysand $54,000 inrelated expenditures. Unquantified losses relatedto guiding and outfitting would alsooccur. It is estimated that replacement of habitat to offset these losses would cost $6,460,000. The"wetland restoration" alternative and any of the combinations studied wouldcompletely offset the losses attributed to the authorized plan. (2) Annual lossof $2,977,000 to the commercial fishery: Reductionsin walleye, whitefish and sauger populations in Lakes Winnipegand Manitoba due tothe introduction of exotic species will decreasecommercial fishing and related revenue by $2,977,000 annually. The "closedsystem" alternative would offsetmost, if not all, ofthe lossespredicted for the authorized