Text Size
Increase text size
Increase text size

Rivers, Lakes and Streams (surface water)

River Flowing Through Canyon


Within Colorado’s borders can be found over 105,344 river miles and more than 249,787 lake acres. The majority of Colorado’s rivers originate in the pristine high alpine environment of the Rocky Mountains and flow downstream through the high desert or high plains regions before leaving the state. 

There are seven major river basins in Colorado: the Arkansas, Rio Grande, San Juan, Colorado, Green, Platte and Republican.


Regulation 85 

summary pdf file of the nutrients regulations adopted by the Water Quality Control Commission is attached.

Below is the Monitoring Panel for the Regulation 85 requirements.  Please note the corrected period of record for the Cooling Tower Monitoring Panel.  More information will be coming soon. Regulation 85 Monitoring Panel / Approved Methods excel spreadsheet  


PLEASE NOTE: Regulation 85 Nutrient Monitoring Data for calendar year 2013 should be submitted electronically by emailing the report form to:
kristy.richardson@state.co.us or arne.sjodin@state.co.us

The monitoring plan objective is to gather, assess and report data regarding the chemical, physical and biological integrity and quality of state surface waters for the Federal Clean Water Act (CWA) 303d list of impaired waters and the 305b report of status of water quality in Colorado as the EPA Integrated Report.


In support of these objectives, the Environmental Data Unit (EDU) maintains a system of state wide stream water quality monitoring sites for collecting chemical, physical and biological data. Each year additional sites are added in a specific “focus basin”, in order to collect additional data in support of future basin wide rule making hearings conducted by the WQCC.


The following document is our sampling plan for the 2012 Fiscal year.

FY12 Monitoring Plan pdf file

Electra Lake, La Plata County

Colorado has approximately 1,533 publicly owned lakes of greater than ten surface acres. The total surface acreage of these lakes has been estimated at 164,029. Significant publicly owned lakes are defined as those natural lakes, reservoirs, or ponds where the public has access to recreational activities, such as fishing and swimming, or where the beneficial uses, such as water supply, affect the public.


Over the last 20 years, the Division has monitored 98 lakes and reservoirs across the State. The lake and reservoir monitoring efforts provide data to evaluate the trophic status of Colorado lakes and reservoirs. The data also are used to assess attainment of water quality standards.


At each lake, depth profiles of dissolved oxygen, pH, conductivity, and temperature are collected at one-meter intervals. Water quality samples are taken from near the surface and near the bottom. Samples are analyzed for a suite of chemical parameters including nutrients, metals, and inorganics. In addition, the surface sample is analyzed for the chlorophyll a content as a measure of trophic status and for the phytoplankton population to determine the algal species composition.


Trophic state is a classification of lakes based on the level of biological productivity (especially algae) and nutrient status. Commonly used indicators of nutrient status and productivity include the amount of algae as measured by chlorophyll-a, water transparency as measured by Secchi disc depth, and in-lake epilimnetic total phosphorus concentration. The trophic state is broadly defined as follows:

  • Oligotrophic: lakes with few available nutrients and a low level of biological productivity characterized by clear water; often supports cold water fish species.
  • Mesotrophic: lakes with moderate nutrient levels and biological productivity between oligotrophic and eutrophic; usually supports warmwater fish species.
  • Eutrophic: lakes with high nutrient levels and a high level of productivity; typically supports exclusively warmwater fish species.
  • Hypereutrophic: lakes in an advanced eutrophic state

Trophic status is an index of water quality only to the extent that trophic condition limits the desired use of a lake (i.e., water supply or recreation). Generally, the effects of lake eutrophication are considered to be negative, especially if the eutrophication is accelerated by human activities. Negative effects include taste and odor problems for water supplies; reduction in water clarity, which is important for many recreational uses; and a reduction in the DO concentration in bottom waters to levels that are lethal to fish. Eutrophication often leads to increased fish production, but at the expense of desired species that inhabit cold deep areas, such as trout.


As part of the lake assessments, the Division also considers data collected by agencies other than the Division. Routine monitoring of publicly owned reservoirs is being, or has been performed, by the USGS, Army Corps of Engineers, Denver Water, and various other entities including cities, regional council of governments, and river basin associations.

The Colorado Department of Public Health and Environment (CDPHE) Water Quality Control Division (WQCD) has the responsibility to monitor and protect the surface waters in the State of Colorado. The Environmental Data Unit (EDU) of the WQCD is responsible for collecting scientifically sound water quality information, using established data collection methods, and assessing those data using a reproducible approach. This approach includes the collection of baseline data, such as temperature information, from waters of the State of Colorado.


Data from Colorado Temperture Monitoring Prgram can be found on this page.

The purpose of Colorado’s Temperture Monitoring Project is to collect in stream temperature data for the following purposes:

  • Used to determine ambient stream water quality
  • To assess physical/biological health of the stream
  • To develop and revise water quality standards
  • To assess trends and to determine if applicable water quality standards are being met.



The objective of the Temperature Monitoring Project is to collect representative water temperatures from the stream. It is therefore, important that collection methods are consistent to minimize data bias, and to ensure that data collected at different locations are collected in a comparable manner.



The Temperature Monitoring Project was launched on June 1st 2009. At this time, approximately 30 temperature loggers were deployed into various streams across the state. Currently, no data has been collected and downloaded. However, it is our intention to post that data here when it becomes available.



If you come across our equipment in Colorado streams and rivers, please do not tamper with it. It is an integral piece in our efforts to protect the environmental quality of Colorado’s waters. If a temperature logger and/or anchoring system are found in a disturbed state please call Aimee Konowal at 303-692-3530 with information regarding location and state of the logger or anchoring system.


Onset¿s TidbiT temperture logger  Anchoring system for  temperature logger.
Figure 1. Onset’s TidbiT temperture logger Figure 2. Anchoring system for temperature logger.

Questions regarding this program can be directed to Aimee Konowal at 303-692-3530.


The Environmental Data Unit has developed a Excel Macro to aid in the analysis of temperature data.

Temperature Analysis Program v4.2

Temperature Analysis Program v4.3

303(d) Listing Methodology

Colorado’s 303(d) Listing Methodology provides a framework for the determination of attainment or non-attainment of assigned numeric water quality standards and designated uses. The 303(d) Listing Methodology is reviewed and updated on a biennial basis in anticipation of 303(d) List and Monitoring and Evaluation (M&E) List Development.


2012 303(d) Listing Methodology pdf file


Assessment Methods and Tools

Most assessment methods used by the Water Quality Control Division are included in the 303(d) Listing Methodology as described above. The following are additional resources used by the Division to assess data.


Guidance for Determining Sediment Deposition Impacts

Policy on Aquatic Life Use Attainment 

Temperture Macro V4.3 and Temperture Macro Instructions pdf file

Assessment Template and Assessment Template Instrustions pdf file



303(d) List and Monitoring and Evaluation List

The 2010 303(d) List of Water-Quality-Limited Segments Requiring TMDLs – 303(d) List and Colorado’s Monitoring and Evaluation List (M&E List) are included in Regulation No. 93. This regulation establishes Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”). This list fulfills section 303(d) of the federal Clean Water Act which requires that states submit to the U.S. Environmental Protection Agency a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.


Regulation 93 - Colorado's Section 303(d) List of Impaired Waters and Monitoring and Evaluation List

 305(b) - Integrated Water Quality Monitoring and Assessment Report

Completed Total Maximum Daily Load Information



To Obtain Data:

The Water Quality Control Division assesses data collected internally by the Environmental Data Unit. Data is also obtained and assessed by USGS, Riverwatch and third parties.


Data can be obtained through the following sites:

National STORET houses WQCD data as well as some third party data.

USGS data is found: National Water Information System (NWIS) Site.

River watch and other third parties store their data with the Colorado Data Sharing Network.

National Water Quality Monitoring Council's Water Quality Portal is another source for data.

Water Quality Control Division Spatial Data can be found on this page.

Colorado Data Sharing Network provides access to many data sources.


Data Submittal Forms:

Bug Data Read Me File

Bug Data Station Predictors Import excel spreadsheet

EDAS Final ID List excel spreadsheet

Master Bug Import File excel spreadsheet

New Taxa Template excel spreadsheet

2014 Data Submittal Template excel spreadsheet