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HomeMy WebLinkAbout1983-09-MUNICIPAL WATER INVENTORY September 1983 CITY OF BOZEMAN MUNICIPAL WATER INVENTORY INTRODUCTION This report describes the current status of the City of Bozeman's municipal water supply. It was prepared by the staff of the Bozeman Public Works Department at the request of the City Commission. The report describes the City's sources of water, the existing water delivery system, historical water demands and the on-going water system improvement program. The report explains why the City needs more water than it has the rights to and discusses several potential sources of additional water. SUMMARY The City of Bozeman obtains its municipal water supply as surface water from three local watersheds. If the City were able to effectively cap- ture all of the water it has a right to use, City water users could consume 13,368 acre-feet (ac ft) of water per year. Because of limitations in exist- ing storage and delivery facilities, however, the City can only reliably de- pend on supplying 6,607 ac ft per year to its customers. This is less than one-half of its water the City has a right to use. In the West, a water right can be lost if it is not put to beneficial use. Other water users have already filed water right claims on water that the City diverts into its system that overflows to local streams due to water delivery system limitations. Should such claimants be successful, City water rights could be lost. At the present time, City of Bozeman municipal water demands exceed by over 20 percent the amount of water it can reliably expect to be able to divert from its water supply sources. This deficit occurs during dry years and is reduced during wet years. Because the City must be able to supply its customers even during dry years, action is needed to eliminate this deficit. Because an in-depth study is needed, we recommend that the City retain an engineering consultant to evaluate solutions to these problems. The consultant's initial efforts should focus on determining how the City can better utilize its existing water rights. Because of the inter- relationshsips between the City's water distribution network and its water delivery system, the total system should be studied so as not to prematurely foreclose cost-effective solutions. Solutions to the City's water supply problems will be expensive. Care- ful consideration of available financing options should therefore be an inte- gral part of the study, as should careful consideration of environmental effects. The problems that the City faces are serious. We are confident, though, that with careful planning and the commitment of a dedicated City Commission, the City will once again be able to reliably supply the water demands of its residents. - G - CITY OF BOZEPAAN MUNICIPAL WATER INVENTORY EXISTING SUPPLY The City acquires its municipal water supply from three separate drain- ages. The drainages are Lyman Creek, Bozeman Creek and Middle Creek. Surface water rights are the source of supply from Bozeman and Lyman Creek. The City acquires stored water from Mystic Lake and Middle Creek Reservoir. A complete listing of the water rights claimed by the City and shares of stock and water purchase contracts for stored water owned by the City is included in Tables 1 -4 of this report. Lyman Creek Surface water diversion from Lyman Creek was developed as the first water supply for the City of Bozeman. The basis of use is decreed water rights amounting to the first 238 3/20 miner inches of water in the creek. The period of appropriation of this right is the entire year and is based on historical use. Water is diverted from the creek and conveyed in an 18" cast iron intake installed in 1941 to the 5.3 million gallon reservoir site. Water is conveyed to town in an 18" cast iron main installed in 1925 to the booster station site. The booster station was installed with the 1957-58 water im- provement projects. The booster station was necessary since Sourdough Reservoir was built 80 feet higher in elevation than the Lyman Creek Reser- voir. The reservoir was built higher to provide adequate water pressure to the expanding southside portion of town. In essence, this has created a separate pressure district and service area north of the Interstate. The total ideal yield of the Lyman Creek decreed water right is 4309 acre feet annually, or 3.9 million gallons per day (MGD) . However, the reliable yield of the drainage is considerably less. Seasonal stream flow characteristics limit the amount of water available for diversion during most of the year. In fact, the period of the year before and after high run-off, stream flow has been less than that needed to operate one of the two large capacity booster station pumps. Therefore, for most of the year, the Lyman Creek drainage supplies only minimal demand north of the Interstate in its gravity flow service area. Water is not pumped from the reservoir in order to provide an emergency water supply and fire protection to the City. The reservoir could be pumped empty in two days at the maximum pumping rate while the rate of inflow during low stream flow would take 41 days to refill. The reliable yield of the drainage is estimated to be 1453 acre feet of water. The reliable yield has been estimated from discussion with Water Division employees. There is no stream flow data which would allow a statis- tical hydrologic analysis of the watershed. However, taking into account the operation constraint predicated by the booster station pump capacities, the reliable yield available for municipal consumption is reduced to 393 acre feet. Approximately 1060 acre feet of water reliably available for diversion from the drainage is lost to the water distribution system. Also, the maxi- mum pumping capacity of the booster station is to 170 miner inches of water. - 3 - The entire value of the Lyman Creek water right cannot currently be accessed through the booster station. Bozeman Creek (I nstream Rights) Once the Lyman Creek water supply became inadequate for the City of Bozeman, Bozeman Creek was developed as an additional municipal source (1917) . The instream water rights claimed by the City total 313 miner inches with varying priority dates. The period of appropriation for this water source has also been historically used as continuous. Water is diverted from the creek and conveyed in an 18" clay tile line installed in 1917 to the presedimentation basin at the mouth of Bozeman Creek canyon. The clay line is being replaced periodically by a 30" concrete lined pipe. Middle Creek Reservoir water is also conveyed to the presedimen- tation basin. Together, these waters are transmitted to the 4.0 million gallon capacity Sourdough Reservoir in a 1917 clay the 18" pipe and a 1957 reinforced concrete 18" pipe. Water is delivered to the City distribution system from the southside reservoir by a 1917 steel 18" pipe and a 1957 steel-cement coated 24" pipe. Improvements to the supply system and pre- sedimentation basin are discussed later in this report. The total ideal yield of the instream Bozeman Creek water rights is 5664 acre feet annually or 5.1 MGD. However, similar to the case of the Lyman Creek supply, seasonal stream flow characteristics limit the amount of water reliably available for diversion. The reliable yield of the water rights from Bozeman Creek is estimated to be 4009 acre feet. This estimate is based on a review of limited existing stream gaging records and dis- cussions with Bozeman Water Division employees. Insufficient information exists to perform a statistical hydrologic analysis of both Lyman Creek and Bozeman Creek drainages. Adequate stream flow records exist for the Middle Creek drainage in order to perform a statistical hydrologic analysis of instream flows. The idea of transferring this information to the Bozeman Creek drainage has been discounted because they are not considered similar drainages. The soil and permeability characteristics of the drainages are dissimilar. Also, the stream flow records for Middle Creek are influenced by the operation of Middle Creek Reservoir. Mystic Lake In 1922 , the City acquired 4 of the 20 total shares of original stock for stored water within Mystic Lake. Mystic Lake is located within the upper reach of the Bozeman Creek drainage. Since that time, the City has acquired additional shares to increase the current total to 10. The water rights uti- lized to fill the reservoir are claimed by the Bozeman Creek Reservoir Company. Upon demand, water is released from the dam and conveyed downstream in Bozeman Creek to the City operated point of diversion. This diversion facility is the same one used to appropriate instream Bozeman Creek water rights. Delay time from release of water at the reservoir to delivery at the intake is about six hours. f - 4 - The total ideal yield of the stored water is 690 acre feet, or 2.1 NIGD for the period of June 15 to September 30. This figure is reduced by actual storage capacity of the dam and a shrinkage factor applied to released water. The reliable yield of water available for diversion downstream is 540 acre feet. The amount of water able to be stored and delivered from Mystic Lake Dam has also been limited by structural and operational deficiencies. A sink hole which developed on the face of the right abutment in 1976 reduced the amount of water stored by the dam. Also, separation of the outlet piping caused serious operational and subsequent structural constraints to the dam which led to partial breaching of the structure in October 1982. Currently, an engineering and geological study is being conducted to determine the feasibility of rehabilitating the structure. This study is be- ing funded by grants awarded to the Water Users Association by the Depart- ment of Natural Resources and Conservation (DNRC) . Middle Creek (Hyalite) Reservoir Middle Creek Reservoir was constructed by the State Water Conservation Board (now DNRC) and completed in 1951 . The water rights utilized to fill the reservoir are claimed by the State of Montana. The City has entered into water purchase contracts with the Middle Creek Water Users Association to acquire stored water. Upon demand, water is released from the dam and conveyed downstream in Middle Creek to the City operated point of diversion. The water is then conveyed in a 21" reinforced concrete pipe and necked down to an 18" rein- forced concrete pipe, installed in 1957 to the presedimentation basin at the mouth of Bozeman Creek Canyon. Currently, the City has contracts to 2705 acre feet of stored water with an option to an additional 50 acre feet. Water released from the reser- voir is reduced by a shrinkage factor. The amount of water reliably avail- able at the point of diversion is 2205 acre feet of water. Under the current water marketing contract between DNRC and the Water Users Association, this water is available to the City only during the irrigation season. The irrigation season is defined as May 1 to September 30. Water which is not used by September 30 is not available to the contractor for delivery during the remainder of the year. In summary, the ideal yield of water claimed by the City for municipal consumption is 13,368 acre feet of water. This equates to 4.36 billion gal- lons of water annually. However, for the reasons previously cited, the City can reliably depend on only 6607 acre feet, or 2.15 billion gallons of water annually. The reliable figure excludes contribution from Mystic Lake. The status of Mystic Lake as a water source is discussed later in this report. ' Table 1 BOZEMAN CREEK STREAM RIGHTS | Date Acquired Priority Period of Purchased From � City Amount [)eta Use Effie Whitney May 25 192O 6 miner inches 1866 Continuous < ' ) Elmer and Gertrude Williams ]an. 16, 1929 50 miner inches 1866 Continuous John and Etta Co|den5tein July 1 , 1930 50 miner inches 1866 Continuous John and Etta Cn(denstain July 25, 1931 50 miner inches 1866 Continuous Elmer and Gertrude Williams Feb. 11 , 1937 25 miner inches 1878 Continuous George Huff Apr. ], 1839 50 miner inches 1866 Continuous George Huff Apr. 3, 1938 25 miner inches 1878 Continuous Paul and Nora Smith Apr. 28, 1948 7 miner inches 1 866 Continuous Harry and Virginia Corning Oct. 21 , 1970 50 miner inches 1883 Continuous \ / TOTAL !DEAL YIELD OF THESE RIGHTS IS 5664 ACRE FEET Table 2 LYMAN CREEK WATER RIGHTS Priority Date Amount Period of Use September 1 , 1864 150 3/20 miner inches Continuous May 1 , 1881 88 miner inches Continuous TOTAL IDEAL YIELD OF THESE RIGHTS IS 4309 ACRE FEET ' Table 3 BOZEK4AN CREEK RESERVOIR COMPANY MYSTIC LAKE Shares Purchased From Date Acquired Amount and Period of Time ( 4 Original Stock 06-27-22 400 miner inches for 14 days or 200 miner inches for 28 days Y� Elmer and Gertrude Williams 02-11-37 150 miner inches for 14 days or 75 miner inches for 28 days � George Huff 04-03-39 50 miner inches for 14 days or 25 miner inches for 28 days ] Harry and Virginia Corning 10-21 -70 200 miner inches for 14 days or 100 miner inches for 28 days 1 Harry and Virginia Corning 09-15-71 100 miner inches for 14 days or 50 miner inches for 28 days 1 (J-B Properties 06-27-73 100 miner inches for 14 days or 50 miner inches fnr 28 days \ � TOTAL IDEAL YIELD |S69O ACRE FEET The total ideal yield is computed from the total volume of miner inches described above; the actual filling of the reservoir yields 1190 acre feet of water which the City claims half, or 590 acre feet ideally. Table 4 MIDDLE CREEK WATER USERS ASSOCIATION HYALITE LAKE Contract No. Purchased From Date Acquired Amount - Acre Fee 3 Montana DNRC 02-08-51 500 4 Montana DNRC 02-08-51 550 88 Montana DNRC 03-21-56 1 ,450 74-A Paul B. Smith 08-04-66 10 6-13 Lucien Benepe 08-11-76 20 15-A-2 Fred Pack 10-03-80 75 70-A-1-B Virgil and Phyllis Jahnke 10-03-80 50 89-A-1-13 Virgil and Phyllis Jahnke 10-03-80 50 TOTAL IDEAL YIELD IS 2705 ACRE FEET WATER DELIVERY SYSTEM The access methods and water system delivery constraints have a direct affect on how the municipal water supply is utilized. The two components of the system, which are the northside supply (Lyman Creek) and the southside supply (Bozeman-Middle Creek) are analyzed in the following paragraphs. Northside Supply The Lyman Creek Supply provides continual water service to all custo- mers north of Interstate 90. When inflows are sufficient (only during high run-off periods) water from this supply is pumped through the booster station to extend water service south of Interstate 90. Water is pumped from this relatively clean supply to offset the reliance on instream Bozeman Creek water which is normally turbid during high run-off periods. The turbidity levels and peak demand use decrease the effectiveness of the pre- sedimentation basins for the southside supply during high run-off. High stream run-off reliably occurs only a short period of the year. It is conservatively estimated to occur during a period of 45 days. Stream flows available during the remainder of the year have been estimated to be less than the capacity of the two large pumps in the booster station. During the normal flow period, which is the remainder of the year, the stream flow is estimated to be 70 miner inches (1 .13 MGD) . The current customer demand north of the Interstate is determined to be 23,000 gallons per day. The difference of 1 .11 MGD is overflowed either the diversion facility or the reservoir and is lost to the City. This amount on an annual basis is 1060 acre feet (or 346 million gallons) . The Lyman Creek supply is treated with chlorine and fluoride at the reservoir site. This system will not benefit from the installation of a water treatment facility on the south side of town. It is economically unfeasible to attempt to pipe this water to the treatment plant site due to geographical distance and elevation difference. Additional treatment has not been pre- viously considered for this water source as turbidity has not been a problem even during high run-off. However, additional measures may need to be taken to protect this source from water-borne parasites, such as giardia cysts which may be introduced into the watershed by external factors. Currently, the City is reviewing alternatives and preparing cost estimates to provide adequate protection of this water source if the need arises. Continual testing is being accomplished to determine the existence of poten- tial stream contamination by parasites. Southside Supply The majority of water service to the City residents emanates from this supply. Treatment currently consists of the application of fluoride and chlorine at the reservoir site. Turbidity has been settled at presedimenta- tion basins located at the mouth of Bozeman Creek Canyon. During period of high run-off, the detention time provided by the size of the basins has not been adequate to produce acceptable drinking water. 6 _ The southside supply has been adequate during summer months. However, after the September 30 shut-off date for delivery of water from Hyalite Reservoir, this supply becomes inadequate to meet demand. The water deficit continues to occur until early spring stream flows increase. During the months of low Bozeman Creek flow, Lyman Creek is also not availa- ble in quantity for pumping to the south side. Remedies are being reviewed by the City to overcome this water deficit. These measures are discussed later in this paper. 7 - MUNICIPAL WATER USE Water use records have been tabulated in the previous years by the Water Superintendent. Two categories of water use records are kept. They are water metered within the supply system and water diverted into the supply system. Water diversion totals are higher than water metered into the distri- bution system. Both sets of records are inadequate to reliably predict actual water usage within the City. Water metered into the distribution system does not accurately represent usage since it includes overflow water from Sourdough Reservoir. Diversion records for Bozeman Creek are based on headgate set- tings since there is no instream flow meter for the supply line. The differ- ence between the diversion record and metered record is not the Sourdough Reservoir overflow since water is also overflowed at the reservoir inlet box. The difference also includes supply and transmission main leakage. Lyman Creek usage figures are accurately measured at the booster pump station. A review of the annual water use records of the past eight years is listed below. Year Metered Water Diverted Water 1975 1 ,182.70 MG Not Available 1976 1 ,967.00 MG Not Available 1977 1 ,955.50 MG Not Available 1978 1 ,996.30 MG Not Available 1979 2,271 .38 MG Not Available 1980 2,302.82 MG 2,507.50 MG 1981 2,124.62 MG 2 ,648,65 MG 1982 2,125.34 MG 2,651 .75 MG The reason the diverted amount of water is higher than usage is to ensure that peak daily demands are met and that the Sourdough Reservoir water level is always providing adequate operating pressure for the distri- bution system. The reason for this is that water use fluctuates greatly during the day, while the City can only provide a constant inflow. Also, in the late fall, the diversion gates on Bozeman and Middle Creeks are set to ensure adequate inflow the entire winter season. Cold weather has frozen one creek or the other and not allowed manipulation of the inlet facility. This safety factor provides an overflow during the winter period. As men- tioned previously, a portion of the diverted amount is also lost as leakage in supply and reservoir transmission lines. The leakage amount is not current definable for the various supplies as well as precise overflow amounts. For these reasons, the analysis of water use is difficult. In the future, the metering devices being installed with the current Water Improvement Projects will provide a satisfactory base for a detailed water use analysis. Based on the information available for the City of Bozeman water use, the following analysis is provided. Water diversion figures are used to represent the amount of water required to meet City demand. This is necessary to ensure the ability to meet peak daily use periods without jeop- ardizing operating pressures and supply. It is found that the rate of di- version is around 310 gallons per capita per day (gpcd) for an annual average. The estimated consumption rate based on the figures supplied from the Water Superintendent is 236 gpcd. The 1982 water diversion requirement and the estimated consumptive requirement is listed below along with a comparison to the reliable yield of the City of Bozeman water use rights and water purchase contracts to depict the status of the adequacy of supply. For now, the value of Mystic Lake water is not included in the reliable yield pending outcome of preliminary engineering for dam reconstruction. Estimated Month-1982 Diversion Rqmnt Consump Rqmnt Reliable Yield January 176.08 MG 136.04 MG 99 MG February 159.49 MG 122.76 MG 99 MG March 175.97 MG 137.54 MG 99 MG April 179.65 MG 141 .12 MG 138 MG May 200.66 MG 188.19 MG 284 MG June 205.98 MG 189.05 MG 206 MG July 345.41 MG 243.58 MG 345 MG August 364.62 MG 277.31 MG 365 MG September 250.11 MG 182.97 MG 209 MG October 226.77 MG 146.58 MG 99 MG November 190.31 MG 134.03 MG 99 MG December 176.70 MG 126.16 MG 99 MG TOTAL 2,651 .75 MG 2,025.33 MG 2,141 MG The figures in the table help to document the water deficit experi- enced by the City of Bozeman. In diverting the amount of water necessary to the system, the reliable supply is less than the required amount by 595 million gallons (MG) of water. In the month of May a yield surplus exists which cannot be captured as it is instream water flows. Therefore, an actual system surplus of water cannot be realized. Some type of additional in-line storage could be used to capture the surplus flow as well as a majority of the difference between diverted and consumed water. This option is dis- cussed later in the report. The supply deficits occur from September to April. During this pe- riod the City has relied strictly on instream diversion for municipal supply in accordance with established use rights. Stream flows in Bozeman and Lyman Creeks at the City points of diversions are not reliably adequate to meet diversion requirements. The deficit is currently being met by pur- chasing water remaining in Hyalite Reservoir after the September 30 cut-off date for water user delivery. The City must acquire a permanent use right to an additional reliable water source to overcome the existing winter defi- cit. Also, as water delivery demand increases, the deficit will begin to appear earlier in the fall and late summer. The acquisition of a qualified right to additional water will be needed in the near future to avoid a summer deficit. WATER SYSTEM AND SUPPLY IMPROVEMENTS The City is in the process of improving the water delivery system to provide for more efficient use of supply. The major improvement is the re- placement of an old (1917) clay supply line running from the treatment plant site to the Sourdough Reservoir. Also, the City is progressively replacing a similar clay line from the Bozeman Creek diversion facility to the treat- ment plant site. Both lines have been highly suspect of leakage. Repairs have been periodically performed when leakage became apparent. Also, the City is installing metering instrumentation at critical loca- tions within the supply system to better provide an adequate indication of actual water diversion and distribution delivery. These improvements, along with others designed to improve internal distribution, are being financed by a revenue bond issue. Since water rates have increased to provide the nec- essary revenue, water demand has reduced this summer. This is in accordance to operators of the water system. Increased water rates and the installa- tion of additional service line meters may have helped to conserve water this year. This apparent conservation may also be due to the wet spring and summer experienced in the area. Additional years of base data compila- tion will help to indicate the source of conservation currently being re- alized. Additional sources of firm or reliable water supply have been inves- tigated and initiated by the City. Two water use permits were submitted to the Montana Department of Natural Resources and Conservation (DNRC) in 1978. One request was for the sever and sell of an agricultural water right on Middle Creek. The second request was for a new appropriation of winter water from Middle Creek. The basis for the sever and sell of the agricultural right was the purchase of the use of 300 miner inches of water from Mr. Del Lichtenberg. City records indicate Mr. Lichtenberg received $26,000.00 in 1978 and $35,000.00 in 1980 from the City for the instream right and 50 acre feet from Hyalite Reservoir. The Hyalite Reservoir stored water has not been transferred within the water users association to City ownership pending the outcome of the sever and sell proceedings. Upon advertisement of the water use requests submitted by the City, numerous objections to the proposals were received by the DNRC. Under Montana water law, DNRC was then required to conduct public hearings to gather testimony before providing a decision in each matter. The City ap- plications were also put on hold pending a Hyalite Creek watershed analysis and review of Hyalite Reservoir operating procedures by DNRC to determine water availability. Upon completion of the analysis, the hearings were scheduled by DNRC for January of 1982. The transfer (or sever and sell) of a water use right cannot be ap- proved if it will adversely affect the rights of other persons. In this case, the City presented information relative to the transfer of only that water which would have been consumed by the crop being irrigated on the total parcel. By taking into account type of crop, seasonal total effective pre- cipitation, field irrigation efficiency and total irrigable acres, it was de- termined that 450 acre feet have been historically consumed on the property which was irrigated. Many of the objections raised were in regard to the change in place of the diversion of this water and also the transfer to another drainage. The farmers who objected also requested the City to divert this water in the non-irrigation season if the transfer was approved. The City Attorney had deed transfers investigated regarding the sale of parcels of the original farm to individuals by Del Lichtenberg. It was reported that language was not included in the deeds to reserve the transfer of water rights even though the property ownership was transferred. The opinion expressed by DNRC in this regard is that a pro-rata share of the original water rights would transfer ownership with the land unless it was explicitly excluded in words on the deed transfer. This poses a question as to who was the legal owner of the water rights at the time of purchase from Mr. Lichtenberg by the City. The application for a new appropriation of water from Middle Creek from October 15 to April 15 also met with strong opposition. In particular, the Montana Power Company presented testimony in essence stating there is no unappropriated water in the Upper Missouri Basin for the period of request. Their contention, along with the U.S. Bureau of Reclamation, is that grant- ing of any new appropriations of water will adversely affect their prior es- tablished water rights for power generation downstream to Great Falls. Other objections were presented regarding depletion of flows in the stream causing a detriment to aquatic life and loss of stock water. The original application was for 600 miner inches of Middle Creek water during the requested period of appropriation. The analysis of the watershed by DNRC suggested this amount of water is not reliably available in the stream at the intended diversion point during the period of appro- priation. Therefore, the request was altered at the hearing for only that water which is felt by the City available for appropriation. Also, a base flow amount of 200 miner inches was conceded by the City to remain in the creek at the point of diversion to appease the Fish and Game and local stock water users. In response to the Montana Power Company and the Bureau of Recla- mation, the City presented information that indicated 85-90 percent of water diverted has been returned as direct run-off back to the basin as water system overflow or waste water treatment plant effluent. In this regard, the City requested the consideration of a non-consumptive user of water. A decision is pending from DNRC on this matter also. Should the City be successful in acquiring both water use rights, this will add 490 acre feet of summer water to the system (including the Lichtenberg Hyalite Reservoir water) from the sever and sell and 2898 acre feet of winter water. These amounts will also be considered reliably available for diversion by the City. Decisions on both requests from DNRC are pending . below. The impact of the additional water is included in the tables listed 1982 Month Diversion Rqmnt Current Rel Yield Revised Rel Yield January 176.08 MG 99 MG 201 MG February 159.49 MG 99 MG 193 MG March 175.97 MG 99 MG 233 MG April 179.65 MG 138 MG 223 MG May 200.66 MG 284 MG 284 MG June 205.98 MG 206 MG 206 MG July 345.41 MG 345 MG 345 MG August 364.62 MG 365 MG 365 MG September 250.11 MG 209 MG 368 MG October 226.77 MG 99 MG 249 MG November 190.31 MG 99 MG 334 MG December 176.70 MG 99 MG 240 MG TOTAL 2,651 .75 MG 2,141 MG 3,241 MG The table helps to indicate that the City will be able to meet short term future water needs with the realization of the water use permits being considered by DNRC. A tabulation of revised winter/summer usage versus yield is listed below. Winter (Oct-Apr) Summer (May-Sept) 1982 Diversion Requirement 1285 MG 1367 MG Current Reliable Yield 732 MG 1409 MG Deficit 553 MG 41 MG 1982 Diversion Requirement 1285 MG 1367 MG Revised Reliable Yield 1673 MG 1568 MG Surplus 388 MG 117 MG As mentioned previously, a late summer deficit occurs because the early summer surplus is realized from insteam flow which cannot be captured and held within the water system. The early summer surplus is neglected in the comparison for the revised reliable yield for the same reason. The figures above help to point out the need for additional pretreat- ment or in-line storage for a buffer between the appropriation of insteam water and actual usage. Additional storage would help stretch the current water rights by capturing overflow water from the system during low usage periods of the day. As mentioned previously, it is not feasible to daily manipulate the diversion facilities and reservoir outlets to provide usage water only. However, capturing overflow water will allow the base diver- sion rate to be reduced and still meet peak usage. This will help to extend the application of existing water rights. Increased in-line storage will also be beneficial if the City acquires the additional water rights sought. As of now, the surplus of winter and summer water would not be diverted. However, as usage increases, water could be diverted in excess of usage in October through December and supple- ment low stream flows of January and February. This storage could also be used to capture system overflow water and reduce the monthly diversion requirements. This would also apply to summer usage. Spring run-off water, within water use rights granted by DNRC, could be used for early summer usage to delay the need for stored water supplementation. Also with popu- lation growth, the peak water usage periods which dictate diversion require- ments will grow. This will produce additional amounts of overflow water under existing system constraints. Appropriately sized storage could cap- ture these water sources which currently lead to deficits and will extend the application of existing water rights. Conservation techniques aimed at peak usage periods could also reduce the base diversion amount which re- duces system overflow. Another type of buffer than additional storage may be instituted to extend the application of water for the City. This would be the use of ground water with pumping facilities. The base rate of instream diversion flow could be reduced to possibly eliminate system overflow with the reli- ance of an instantaneous water source such as ground water to meet peak usage periods of the day. The feasibility of this alternative needs indepth study for determination of potential yields of wells and development costs. Also, the issue of water rights enters into this potential municipal water source. Leakage within the distribution system may be in excess of anticipat- ed amounts due to relatively high water pressures. Potential leakage can be detected by significant pressure drops measured within the system. The City has not undertaken this type of water system analysis in the past. The City may find it beneficial to consider the possibility of installing pres- sure reducing valves in appropriate areas to divide the City into separate pressure districts and reduce overall pressure and the potential for leakage. Another benefit of reducing pressure in town may be the extension of gravity flow service area of Lyman Creek. By reducing the south side supply pressure to the gravity flow pressure head of the Lyman Creek supply in the vicinity of the booster station, north side gravity flow service area could be extended south of the Interstate. Water flowing in Lyman Creek could be put to its full potential within the previously cited decreed water rights without the reliance on perpetual energy costs. POTENTIAL SOURCES FOR ADDITIONAL WATER The City has attempted to acquire additional water for municipal con- sumption in the recent past. The decisions awaited from DNRC are expected within the next few months. However, in each case the City can expect to be taken to district court by parties appealing the decision of DNRC if favorable to the City. Also, the City should be prepared to tap other sources if the DNRC decisions are unfavorable. The potential sources which could be investigated by the City are listed below. The order of listing is not intended to suggest priorities. Instream Diversion Decrees from the DNRC hearings officer may indicate a period of water appropriation which may not be in conflict with senior priorities. If this is the case, a determination of how much water may be available and the size and cost of needed storage will have to be examined to determine the feasi- bility of this option. Bozeman Creek and Middle Creek should be looked at first as they have the greatest potential for stream flow amounts and the City has diversion and gravity delivery systems previously installed. Other local streams may have flood flows in excess of existing use rights but depending on the quantity may be cost prohibitive to the City for installation of diversion, treatment and delivery facilities. Acquisition of flood flow rights would only benefit water supply strictly during its time of occurrence without additional storage. For this option, the cost of installing additional storage will have to be included in determining its benefit. The quality of water during flood flows will also require treatment including settling and filtration. Acquire Storage Water Two sources of stored water are used by the City. Acquisition of additional shares of water within each project is a potential viable source. Currently, the City is not considering the acquisition of additional shares of Mystic Lake pending the outcome of the engineering feasibility study for rehabilitation. Also, depending on the cost per share for potential rehabi- litation, the City may acquire all shares within the Association and increase the reliable supply. For the same matter, the City may not participate in rehabilitating the structure depending on the cost per share and/or financ- ing options available. Recently, 50 acre feet of water from Hyalite Reservoir sold for $18,500.00. Annual operation and maintenance charges of about $0.90 per acre foot per year are assessed above the purchase price. Also, the DNRC is now investigating the options and costs for rehabilitating and repair of this structure. The consulting engineering firm of HKM Associates from Billings is preparing the analysis. The firm has contacted the City in search of potential users (and purchasers) of additional useful storage which may be a part of the rehabilitation. New storage water was made available to users from the rehabilitation of Cooney Reservoir at about $2.50 an acre foot per year. This rate relies heavily on construction price and grants/low interest loans which may be available to the State at the time of construction. It should be kept in mind that realization of actual completion of construction may be years if feasible. Groundwater Development Groundwater can provide a potential instantaneous source of water the City does not currently enjoy. Depending on the yield of wells devel- oped will determine the potential benefits of this source. Geologic and hydrologic field investigations are necessary to make a reliable prediction of this source. Depending on the yields expected from wells and their location, a water use permit for groundwater could be contested by the same parties as the surface water diversion applications submitted by the City in 1978. Flood flows may also be stored as groundwater recharge and recalled by a well field. This could save a significant cost for pretreatment storage if flood flow rights were achieved by the City. Construct Storage Facility ( Instream) The Soil Conservation Service conducted a study in the late 1970's to investigate the feasibility of siting a storage facility. Early in the study, preliminary costs were made available which indicated a project as being too expensive for agricultural use. Therefore, municipal water and flood storage project sites were further investigated. In the 1980 final report, the SCS identified potential sites in Bozeman Creek and Limestone Creek for a stor- age project. With all considerations taken into account, the cost to the City were identified to fall in the range of $100 to $150 an acre foot per year for the life of the project. At the time of the study, this range of figures was determined by the City to be cost prohibitive. Further analysis by the SCS was terminated. As is the case with dam rehabilitation, realiza- tion of a finished project will take years. Filling of each potential dam site would have to rely on capturing flood flows occurring at a time not to ad- versely affect downstream senior priorities. Contract Water from Bureau of Reclamation The Bureau of Reclamation has been recently contacted regarding the contracting or "renting" of their purported water right in the Upper Missouri Basin. The decision of DNRC regarding the application of the City for a new appropriation of winter water from Hyalite Creek will either uphold or deny the claim of the Bureau of Reclamation or MPC. If their purported right is upheld, the City may have to consider this option. Preliminary discussions indicate the allowance of the City to rent water from the Bureau at the rate of $20-$30 an acre foot per year. The basis for the charge between diverted and consumed water will need to be resolved during negotiations. Diverted water to overcome current winter deficits would cost the City about $60,000.00 per year. Consumed water during the deficit period would cost the City about $9,000.00 per year. The process involved would be to submit a request to DNRC to alter the point of diversion of a portion of the Bureau's water right. Diversion of this water would not affect senior priorities in the winter other than stock water. Diversion of summer water upstream from Canyon Ferry would definitely affect senior priorities and would not be approved by DNRC. 15 - One benefit of this arrangement, if approved by DNRC is the term of agreement with the Bureau would be 40 years. The "rental" rate would be able to be renegotiated every five years. - 16 - RECOMMENDATIONS The City should investigate alternatives and methods to better utilize the existing water rights claimed. The diversion rate and assumed consump- tion rate per capita suggest the water can be stretched to further use. Capturing system overflow with pretreatment storage will provide an addi- tional 30 percent of diverted water for municipal consumption. Also, con- servation efforts, transmission leakage repair and reduced operating pres- sure could reduce the consumptive rate about 25 percent of the current es- timation. Current water rates may be the impetus for conservation. The alternatives which have been previously discussed are pretreat- ment or in-line storage, groundwater to meet peak usage and reduced opera- ting pressure to increase the Lyman Creek service area. Depending on the outcome of the water use requests, the City may acquire more water from the Bozeman Creek and Hyalite Creek watersheds. This is the first priority as facilities are in place to bring water to the City. Other drainages can be investigated but will probably need to be fed to the water treatment plant site. All the options discussed in this paper should be further investigated and assigned a production or construction cost per acre foot or million gal- lons of water provided. This will help to focus on the involvement of the City with rehabilitation of Mystic Lake and Hyalite Reservoir, groundwater development, new storage construction, purchasing rights or "renting" water. The basis for the identification and development of costs should be indepth, qualified analysis. This has not been provided in the past. As a last resort, the City can consider condemnation of water for public domain or re-use of waste water treatment plant effluent.