Information Availability

The WQDB and associated data files are available at (http://pubs.usgs.gov/ds/471/). 

These files contain the actual WQDB Microsoft Access database (WQDB.mbd), commaseparated-values (CSV) files of each of the eight database tables, and CSV files, 

representing the output of pre-defined sample queries, which combine data from select 

tables. The data from the pre-defined queries are also directly available from the 

GCMRC database at http://www.gcmrc.gov/dasa/tabdata/damsQuery.aspx. Further 

assistance and other data formats are available from the author.

WQDB Metadata

1. These data represent the results of water-quality monitoring activities in Lake 

Powell and from Glen Canyon Dam releases. These data were collected by the 

Bureau of Reclamation’s Upper Colorado Regional Office and Glen Canyon 

Environmental Studies program (1964-1996) and subsequently by the U.S. 

Geological Survey’s Grand Canyon Monitoring and Research Center (1996-

2013).

2. These data are part of the WQDB, a Microsoft Access relational database that 

contains the results of Lake Powell water-quality monitoring activities from 1964 

to 2013. The WQDB is comprised of 8 tables of related information and several 

pre-defined queries to display different types of information from the database. 

The following tables make up the WQDB:

Table Name Description

tblStations A listing of Lake Powell sampling stations, geographical coordinates, and 

locations within mainchannel and tributary arms of the reservoir

tblSurface A listing of site visits to various sampling locations

tblProfiles Depth-profiles of common water-quality parameters associated with site 

visits

tblSecchi Secchi-depth transparency observations associated with site visits

tblSamples Water sample collection information with links to sample analyses

tblAlkalinity Field alkalinity determinations performed on collected samples

tblMajor Ions Results of laboratory analyses for the determination of major ionic 

constituents

tblNutrients Results of laboratory analyses for the determination of nutrient 

compounds of phosphorus and nitrogen

3. The data represented in these files are completely described in the following 

report: 

Vernieu, W.S., 2015, Historical physical and chemical data for water in Lake 

Powell and from Glen Canyon Dam releases, Utah-Arizona, 1964–2013 (ver. 3.0, 
February 2015): U.S. Geological Survey Data Series 471, 23 p., 

http://dx.doi.org/10.3133/ds471.

Historical and current methods are described in the body of the report. Database 

structure and contents of data tables are described in detail in the report appendix. 

Further assistance may be obtained from the author:

William S. Vernieu, Hydrologist

USGS – Grand Canyon Monitoring and Research Center

2255 N. Gemini Dr.

Flagstaff, AZ 86001

(928) 556-7051

bvernieu@usgs.gov

4. The geographic coordinates of sampling locations were determined with handhelp geographic positioning systems and represent the approximate locations of 

sampling activities. Actual reservoir sampling activities may take place within a 

100-m radius of the given sampling location.

5. The following predefined queries are included in the WQDB. Each of these 

queries may be subqueried for selected Station Groups or date ranges.

Query Name Description

qryStation Groups-Primary A listing of the 31 primary station groups of the 

current monitoring program

qrySite Visits at Primary Stations Site visits at the 31 primary station groups

qryProfiles at Primary Stations Water-quality depth profiles at the 31 primary 

station groups

qryMajor Ions at Primary Stations Results of laboratory analyses for the 

determination of major ionic constituents at the 

31 primary station groups

qryNutrients at Primary Stations Results of laboratory analyses for the 

determination of nutrient compounds of 

phosphorus and nitrogen at the 31 primary 

station groups