Upper Los Pinos Water Quality Report

Home Browse Search

estimated by plotting the site on a desldop mapping program (Maptech Terrain NavigatorT""), then the latitudes and longitudes were transferred from the mapping program to the spreadsheet. Most of the site locations were referenced to the horizontal datum of NAD 1927 and vertical reference datum NGVD 1929. The Eicel spreadsheet data ~~-ere eiported to a dBase format. then the dBase file «as imported into ArcGISr""--a geographical information system (GIS) quid mapping ana1~ sis program. Sites locations based on the horizontal reference datum NAD 1927 were converted to the NAD 1983 horizontal reference datum by the GIS program. Vertical datum corrections were not conducted. Spatial data were obtained from digital line graph (DLG) data available from the USGS, digital map la~-ers available from the Natural Resource Conservation Service (MRCS), and digit<11 spatial data available from La Plata Count~~, Colorado. The site locations were overlaid on spatial features (such as streams, drainages, and count~T boundaries). Maps and graphs were imported into Adobe Illustrator"" for editing, then emported into the desktop publisher Adobe Frarnemalcer"" for the writing of this report. Quality Assurance and Historical Laboratory Analysis Methods Qualit~T assurance of water-qualit<- data do«mloaded from the intemet or entered from hard copies can on1~- be verified by the source agenc~~ or laboratoy-. There are. however, a few measures of qualit<- assurance that were conducted for this report. For sites that have historical data, plotting of the data over trine can highlight outliers or incorrect ~i-ater- qualit~- analyses. The dates of collection and anal~-sis of the water-qualit<- data span from 198 to 2003. Laboraton- anahytical methods, accuracy. and precision of reported concentrations have changed over time. The main improvements in analytical methods have been lo~yer detections lunits for metals and nutrients; however, changes in laboratory practices and standards have resulted ili higher confidence in laboratory analyses ili later years. As a rule of thumb, there is generally- less confidence in anal~-ses from the 1960's and 1970's. and greater confidence in analyses from the 1980's to the present. For the purposes of this report, the data are accepted as reported b~- the source agency or laboraton-, and the dat<2 are included in observations of trends overtime. The reader is advised to consider changes in analti-tical methods in the interpretation and understanding of historical ~yater-quality- data. DATA SYNTHESIS For the purposes of this report, data s~~nthesis means compilation and interpretation of available «ater-qualiti<- data. Limited interpretations are provided so readers can derive their o~~n conchisions. The ultimate goal is to describe the waters that are of good qualit~T and develop a ~~-atershed plan to make sure that the ~yaters remain of good quality-. Summary statistics of ~~ ater-quality- data from the upper Los Pinos River «-atershed are sho«7i in table 2. There were no biological data in the upper Los Pinos River «atershed available at the trine of the «citing of this report. A general measure of water qualit<- in the upper Los Pinos River watershed is specific conductance (SC), which is the abiliti<- of a fluid to conduct electricit<-. and is measured in the field with a specific conductance meter. Specific conductance (SC) can be compared with total dissolved solids (TDS). For samples that reported TDS concentrations, plotting SC and TDS is described b~- a linear relationship (fig. 4). ~ 400 W H J w 350 a ~ 300 ~ 250 z ~ 200 0 ~ 150 W ~ 100 0 ~_ ~ 50 J H O 0 Dissolved Solids of Ground Water = [(0.51 'Specific Conductance of Ground Water) + 31] RZ = 0.94 . STREAMS • ~ GROUND WATER • VALLECfTO RESERVOIR Dissolved Solids of Streams and Reservoir = [(0.56' Specific Conductance of Streams and Reservoir) +4] RZ = 0.67 200 400 600 800 1,000 SPECIFIC CONDUCTANCE, IN MICROSIQVIENS PER CENTIMETER Figure 4. Relation of specific conductance to dissolved solids in sh~eams, ~n~ound water, and Vallecito Reservoir of the upper Los Pinos River watershed. The SC and TDS relationship can be useful for the general public to estnnate total dissolved solids ~yithout peifonning an expensive laboratory anal~-sis. ~' ~ SouthwestHydro-Logic 9