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Stream Flow Measurement Points <br />There are approximately 54 active stream flow gages within the San Luis Valley. Note the 54 <br />includes 12 new stream gages installed by the State in 1998 and 1999 as part of RGDSS. One of <br />these stations is operated by the U.S. Geologic Survey (USGS) while the remaining stations are <br />operated under a cooperative agreement between the USGS and the State of Colorado. These <br />gages play an integral role in the administration of basin water rights and the Rio Grande <br />Compact. There are ten measurement points used to monitor inflow and outflows for determining <br />Compact delivery obligations by river (Rio Grande and Conejos) and actual state-line deliveries, <br />and for intrastate accounting purposes within Colorado. These ten gages are listed under the <br />section titled Rio Grand Compact Administration, subsection Day to Day Administration. <br />Rio Grande Compact Administration <br />The Rio Grande Compact was signed by the states of Colorado, New Mexico and Texas in 1938 <br />and ratified by Congress in 1939. Since 1968, the Compact has had a substantial influence on the <br />manner in which water rights are administered in the Rio Grande basin in Colorado. The portion <br />of the Compact that is most important to daily water administration in Colorado is Article III, <br />which is provided as Attachment 1 to this memorandum. The following discussion provides <br />information gleaned from interviews with Division 3 concerning their administration of water <br />rights to meet Compact requirements. <br />Delivery Requirements to New Mexico <br />The Rio Grande Compact sets annual state-line water delivery obligations from the Rio Grande to <br />New Mexico by Colorado based on the amount of flow at several "Index" gaging stations within <br />Colorado. Scheduled delivery obligations by Colorado to the state-line are determined as a <br />percentage of flows past these gages. The percentages are different between the Index gages <br />located on the Rio Grande and the Conejos River. In addition, the percentages differ depending <br />on the annual amount of flow passing these gages. These percentages, shown in graphical form, <br />are presented as Attachment 2. <br />Total Compact delivery obligations to the state-line are determined as the sum of the obligations <br />from the Rio Grande and Conejos drainages. The Compact delivery measurement point for the <br />Rio Grande Basin is located downstream of the Rio Grande-Conejos confluence near the state- <br />line (Rio Grande near Lobatos, Colorado LD. No. 8251500). In each year, Colorado is allowed a <br />"paper credit" of 10,000 acre-feet, which effectively reduces the delivery requirements described <br />in Article III by this amount. From the perspective of New Mexico, the source of the state-line <br />delivery (either Conejos or Rio Grande) is irrelevant as long as the total obligation is met. <br />Deliveries to the state-line are not required to strictly adhere to the Compact delivery tables on an <br />annual basis (Article VI). The Compact allows for the accrual of Compact "credits" and "debits.' <br />Colorado may under-deliver (a debit situation) by as much as 100,000 acre-feet in any one year, <br />and accrue up 100,000 acre-feet debit over multiple years. Colorado may also receive credit for <br />over-delivery to the state-line up to 150,000 acre-feet per year, and accrue an unlimited credit <br />amount over multiple years. This credit/debit provision of the Compact provides Colorado with <br />flexibility in managing water use, although current administrative practices attempt to match <br />actual deliveries to scheduled obligations each year as closely as possible. <br />In a Memorandum of Understanding signed in 1981 (resulting from the "Rules and Regs." case <br />initiated in 1979 -Case No. W-3466) by the Rio Grande Water Users Association and the <br />C:Acdss\Div3_Mem2.doc Division 3 Interview June 28, 1999 -Page 3 of 8 <br />