FLOOD08247 - Laserfiche WebLink

Home Browse Search

Of the land in the Town of pagosa Springs, 45.4 percent is residential and 8.1 percent is commercial. In Archuleta County, the land is 14.1 percent residential and 2.5 percent commercial. The flood plain of the Town of Pagosa Springs is partially developed, and some commercial development that will fall within the flood plain is planned. Some residential flood plain development is also planned in Archuleta County. The San Juan River, which flows through the Town of pagosa Springs, rises from the San Juan Mountains in southwestern Colorado and flows southwesterly. It joins the Animas River at approximately the Colorado-New Mexico State line. A small tributary, McCabe Creek, enters the San Juan River from the north, in the west- central part of Pagosa Springs. The Rio Blanco, which also oriainatcs in the San Juan Mountains, flows southwesterly and joins the San Juan River approximately 3 miles north of Truillo, Colorado. The drainage area of the San Juan River is approximately 298 square miles at Pagosa Springs. The McCabe Creek watershed, which is a tributary to the San Juan River, covers approximately 20 square miles. The Rio Blanco watershed, which is also a tributary to the San Juan River, Covers approximately 157 square miles at the down- stream end of the study area. The topography of the study areas in Archuleta County is primarilv mountainous regions lying in the southernmost part of the state. The headwaters of the San Juan River start in the southern slopes of the San Juan Mountains at an elevation of approximately l3,con feet and fall to an elevation of approximately 7,000 feet at Pagosa Springs, which results in an average fall of an elevation of approx- imately 250 feet per mile. The headwaters of the Rio Bla~co are at an elevation of approximately 12,000 feet and fall to an elevation of approximately 7,000 feet at the downstream end of the detailed study area. Through this reach, the Rio Blanco has an average fall of approximately 200 feet per mile. The average annual precipitation in the study areas is approxinatcl \' 20 inches, of which 8 inches is observed in the period from ~ay through September. The annual mean temperature is 42 of; the mont:ll~' mean temperature varies from 640p in July to 190r in January. Humidity is generally quite low, allowing rapid evaporation. 2.3 Principal Flood Problems Major flooding along the San "Tuan River through PaCOS2 Sprinos usually occurs during the autumn and can be attribute~i to ralnstc.YtlDS of long duration. Minor flooding in the sprinq, at morc frc'c:ul'lit in terval s, is caused by rapid snoWInO 1 t dur inq abn~rmall \' \,'a l-n weather. Localized cloudbursts durin<) the summor month~~ ;~a\',-. caused periodic floodinq of small st~eams in and arollIlc~ T'a-,TOc.:;~: Springs and along the Rio Blanco River in Archuleta C(.unt~.. 5