Upper Los Pinos Water Quality Report

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VALLECITO RESERVOIR, SOUTHERN END SURFACE OF RESERVOIR ~ 1 w zW w~, zz ~ U 1 U ~ ~ W ~a z~ oZ W U ~ ~ LL W a ~ v7 U 7 W oW7 F J wawi7 ~ j W ~o om7 >a WW7 (/J W W LL ~Z7 160 (A) SPECIFIC CONDUCTANCE OVER TIM 40 ~0 MISSIONARY RIDGE WILDFIRE _ JUNE-JULY 2002 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 s7a • ~ ^ ~~ ( ~ B) RELATION OF SPECIFIC 660 ~ •~ • ~ CONDUCTANCE TO . ~ ~ RESERVOIR ELEVATION ~ .650 ~ ~ ,640 ... ; • . ~ .. .630 • ~ . . •. sza • ~ PRE-FIRE ^ .610 ^POST-FIRE ^ saa 50 60 70 80 90 100 110 120 130 140 SPECIFIC CONDUCTANCE.. IN MICROSIEMENS PER CENTIMETER 7,670 7 ssa J O w 7,650 J 7.640 wW ~ O 7.630 om >a ~ w 7.620 W LL ~z 7,610 5 7 9 11 13 15 17 19 VISUAL DEPTH (SECCHI DEPTH).. IN FEET ^. .~ ^ ~ . . • ~ ^ ^ ~ (C) RELATION OF SECCHI • PRE-FIRE DEPTH TO RESERVOIR ELEVATION ^ POST-FIRE Figure 15. Variation of specific conductance with time, and relation of water properties with reservoir elevation, Vallecito Keservoir, southern end. surface of the reservoir. WATER-QUALITY STANDARDS, CRITERIA, AND GUIDELINES The primai-~- concerns for water-quality- stan- dards in the upper Los Pinos River watershed, at this time, are aquatic-life standards for fish and other aquatic resources. If the waters of Los Pinos River are further developed for public water supply (To~~m of Ignacio currently uses Los Pinos River water for public supply), then there mad- be more concerns about the water quality regarding human health. Aquatic- life standards vai-~- according to acute tonicity (sudden enposure) and chronic tonicity (long-term enposure). The standards may apply to the dissolved and total recoverable phases of the constituents. Water-quality standards for stream reaches in the upper Los Pinos River watershed are described in table 3. In addition, the tonicity values are dependent on hardness of the water because higher hardness values tend to mare dissolved metals less tonic (table 4). Hardness mad be calculated as the sum of the divalent (+2) cations (mainly calcium and magnesium) in a water sample. Some of the table value standards (such as selenium) are reported as fined numbers because of entensive research into the tonic effects of these constituents. The summan' statistics sho~~m in table 1 can be compared to the standards in table 2. For enasnple, the manimum chromium (Cr) concentration in a stream sample was 30 µg/L (micrograms per liter, or parts per billion) (table 1). The standard for chromium ~yith a valence state of 3 (CrIII) is ~0 µg/L (table 2); therefore. the chromium standard is not enceeded in streams of the Los Pinos River watershed. Most of the ~yater-quality samples in the upper Los Pinos River watershed are yell within the rater-quality standards. There ~yere enceedances for ammonia, total iron, pH, total phosphorus, selenium, zinc, and fecal colifonn. Low dissolved-onygen concentrations in Vallecito Reservoir ~yere below the standard of 6.0 mg/L (milligrams per liter). There have been vei-~ fey water-quality samples collected in the upper Los Pinos River watershed since 2000; therefore- the effects of the Missionaw Ridge wildfire are not adequately represented by the data. SUGGESTIONS FOR A WATERSHED PLAN Watershed management is an approach to water- resource protection that enables individuals, groups, and institutions ~yith a stake in management outcomes (often called stakeholders) to participate in identifS-ing and addressing local issues that affect or are affected by watershed functions. Watershed management is not a single strategy, but is a general approach to water resource protection that recognizes the 28 Water-Quality Data Synthesis for the Upper Los Pinos River Watershed, In cooperation with the Colorado Watershed Protection Fund and Southwestern Colorado, and Suggestions for a Watershed Plan, 2005 the San Juan Resource Conservation and Developrnent Council