Upper Los Pinos Water Quality Report

• Document ID: hr_0007
• Contract/PO #: PO 05-64
• County: La Plata
• County: Hinsdale
• County: San Juan
• Stream Name: Los Pinos River
• Basin: San Juan/Dolores
• Sub-Basin: Upper San Juan 14080101
• Water Division: 7
• Title: Water_Quality Data Synthesis for the Upper Los Pinos River Watershed, SW Colorado, and Suggestions for a Watershed Plan, 2005
• Date: 1/1/2005
• Prepared For: CWCB
• Prepared By: Southwest Hydro-Logic
• Watershed Pro - Doc Type: Planning Report

CONTENTS
Abstract ......
Introduction
Purpose and Scope ............................................................................................................... ....................................... 3
Physical Setting. Climate. and Hvdrology ..................................................................................... ....................................... 3
Methods of Inyestigation .............................................................................................................. .......................................
L1t0ratUrO ROVIe~j ................................................................................................................. ....................................... ~
Data COlllpllatlon ................................................................................................................. .......................................
Geographical hiformation S~, stem ....................................................................................... ....................................... 6
Qualit<~ Assurance and Historical Laboratory Analysis Metliods ........................................ ....................................... 9
Data Synthesis ................................................................................................................................ .......................................
9
High Altitude Lakes ............................................................................................................. ....................................... 16
StrealIlS ................................................................................................................................. ....................................... 1
E~
Vallecito Reseryoir ............................................................................................................... ....................................... ?0
Water-Quality Standards, Criteria. and Guidelines ........................................................................ ....................................... 28
Suggestions for a Watershed Plan .................................................................................................. ....................................... 28
Sulnlnan ........................................................................................................................................ .......................................
31
References Cited ............................................................................................................................ .......................................
3?
List of Figures
Figure 1. Map showing hydrologic unit codes in the Los Pilios River watershed of Archuleta, Hinsdale, La Plata, and
San Juan Counties- Colorado ................................................................................................................................................ ..... 2
2. Map showing land ownership in Los Pinos River ~a°atershed of Archuleta. Hinsdale,
La Plata. and San Juan Counties- Colorado ........................................................................................................................ ..... 4
3. Graph showing streamflow discharges in Uallecito Creek for water nears 1962-2003 .......................................................... ..... ~
d. Graph showing relation of specific conductance to dissolved solids in sh~eams, ground water. and Uallecito Reservoir
of the upper Los Pilios River watershed ............................................................................................................................. ..... J
~. Map showing location of water-quality sites in the upper Los Pinos River watershed .......................................................... ..... 17
6. Cn~aphs showins concenh~ations of selected water-qualih constituents over time for
high-altitude lakes in the upper Uallecito Creek watershed ................................................................................................ ..... 18
7. Graphs showing concentrations of selected water-qualitt~ constituents over time for
Ulllecito Creek at the USGS ,aging station ....................................................................................................................... ..... 19
8. Map shoeing location of eater-qualih' sites in the Vallecito Reservoir area of
the upper Los Pilios Rivzr watershed .................................................................................................................................. ..... 21
9. Map showing location ofwater-quality- sites and total arsenic concentrations where reported in
surface- and ground-water samples .................................................................................................................................... ..... 22
10. Map showing location of water-qualih~ sites and fecal coliform concentrations ~a here reported ......................................... ..... 23
11. Graphs showing specific conductance, pH, and nitrite plus nih~ate over time in Los Pilios River above
Uallecito Reservoir and Los Pinos River below Uallecito Resell-oir .................................................................................. ..... 24
12. Schematic shoein« thermal stratification and circulation (overturn) in a lalce .................................................................... ..... 2~
13. Graphs showing Profiles of water properties in Uallecito Reservoir at the southern end of the lake grouped by
season for selected years of data ......................................................................................................................................... ..... 26
14. Graphs showing variation of selected constituents over time. and relation of water properties to
reservoir elevation_ Uallecito Reseit~oir, southern end (deepest part) of the reservoir. bottom of the reservoir ................. ..... 27
1 ~. Graphs shoe°ing ~--°ariation of specific conductance with time, and relation of ~a°ater properties
with reservoir elevation. Uallecito Reseil~oir, southern end. surface of the reservoir ........................................................ ..... 28
List of Tables
Table 1. Water-quality sites in the upper Los Pinos River watershed and data base identifiers ............................................................ ..... 7
2. Summan statistics for water properties and constituent concentrations in streams_ hish altitude lakes.
;round water. and Uallecito Reservoir in the upper Los Pinos River watershed ..... ~ ......................................................... ..... 10
3. Sh~eam classifications and water-qualih' standards for the upper Los Pinos River watershed ............................................... ..... 29
4. Table value water-qualih standards for the upper Los Pinos River watershed ...................................................................... ..... 30
CONTENTS