State of New Mexico > Environment Department > Surface Water Quality Bureau

Surface Water Quality Bureau
Monitoring & Assessment

US EPA-Approved TMDL
for the Rio Chama Watershed
[Abiquiu Reservoir to Headwaters]

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The Rio Chama above Abiquiu Reservoir, May 1999...  Download the 2.6 MB PDF today!

The Surface Water Quality Bureau (SWQB) conducted a water quality survey of the Rio Chama Basin of northcentral New Mexico in 2007. Water quality monitoring stations were located within the watershed to evaluate the impact of tributary streams and ambient water quality conditions. As a result of assessing data generated during this monitoring effort, impairment determinations of New Mexico water quality standards (WQS) include the following:

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BACTERIA (E. coli) in the Rio Capulin (Rio Gallinas to headwaters), Rio Chama (El Vado Reservoir to Rio Brazos), Rio Chama (Rio Brazos to Little Willow Creek), Rio Chamita (Rio Chama to the Colorado border) and Rio Puerco de Chama (Abiquiu Reservoir to Highway 96);

Heidi Henderson
TMDL Development

(505) 827-2901

US EPA-Approved TMDLs 2.6 MB Download the 2.6 MB PDF file today...
WQCC Approval Order 104 kb Download the 104 kb file today...
US EPA Approval 362 kb Download the 362 kb file today...
Bulleted item Water Quality Survey Summary for the Upper Rio Chama Watershed - 2007
Bulleted item 2007 Lakes Water Quality Assessments including Abiquiu and El Vado Reservoirs - 2007
Bulleted item Lower Rio Chama Watershed TMDLs - 2004
Bulleted item Upper Rio Chama Watershed TMDLs - 2003
Bulleted item Rio Chamita TMDLs for ammonia, fecal coliform and total phosphorus - 1999
Bulleted item Rio Chamita TMDL for temperature - 1999
Bulleted item Water Quality Survey Summary for the Lower Rio Chama Watershed - 1999
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PLANT NUTRIENTS in the Rio Chama (El Vado Reservoir to Rio Brazos), Rio Chama (Rio Brazos to Little Willow Creek), Rio Chamita (Rio Chama to the Colorado border) and the Rio Tusas (Rio Vallecitos to headwaters);

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SPECIFIC CONDUCTANCE in Canjilon Creek (perennial portions Abiquiu Reservoir to headwaters) and;

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TEMPERATURE in Canjilon Creek (perennial portions Abiquiu Reservoir to headwaters), Rio Chama (El Vado Reservoir to Rio Brazos), Rio Chama (Little Willow Creek to the Colorado border), and Rio Puerco de Chama (Abiquiu Reservoir to Highway 96).

SWQB data collections documented continued impairments of the New Mexico WQS. These are “old” impairment listings that already resulted in a TMDL but continue to be impaired based on the 2007 data and assessments include:

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BACTERIA (E. coli) on the Rio Chamita (Rio Chama to the Colorado border).  A fecal coliform TMDL was previously developed for this AU and it is now impaired for E. coli.;

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TEMPERATURE on the Rio Chama (Rio Brazos to Little Willow Creek) and the Rio Chamita (Rio Chama to the Colorado border).

The TMDL document addresses the above-noted impairments as summarized in the Executive Summary tables starting on page 4.  The data used to develop these TMDLs were collected during the 2007 Rio Chama survey with follow-up collections in 2010. The 2007 study identified other potential water quality impairments which are not addressed in this document. Additional data needs for verification of those impairments are being identified and data collection will follow. If these impairments are verified, subsequent TMDLs will be prepared in a separate TMDL document.

SWQB hosted a public meeting in Tierra Amarilla, New Mexico on March 7, 2011 to discuss the Public Comment Draft Rio Chama Watershed TMDL. Notes from the public meeting are available in the SWQB Administrative Record. The following changes were made to the Final Draft document in response to staff comments either during or after the public comment period:


Based on staff comment, the TMDL allocations for temperature on Rio Chama (Little Willow Creek to CO border) were corrected in the Executive Summary table. Likewise, the Load Allocation for E. coli for Rio Chama (Little Willow Creek to CO border) was corrected in both the Executive Summary table and Table 3.7.


Available nutrient data for Los Ojos Fish Hatchery was added to Sections 4.4.1 and 8.1.

Written comments received during the 30-day public comment period and SWQB responses to the Public Comment DRAFT TMDL were incorporated into a Final Draft version as Appendix F. The Final Draft version was presented to the Water Quality Control Commission (WQCC) for approval at their regular meeting on Tuesday, July 12th, 2011.  Only a slight alteration in the text of one sentence was required for approval.  The United States Environmental Protection Agency (US EPA) gave final approval without substantive changes to the WQCC-Approved TMDL on August 16th, 2011.

The Monitoring and Assessment Section will collect water quality data during the next rotational cycle.  The next scheduled monitoring date for the Rio Chama Watershed is 2012 at which time TMDL targets will be re-examined and potentially revised as this document is considered to be an evolving management plan.  In the event that new data indicate that the targets used in this analysis are not appropriate and/or if new standards are adopted, the load capacity will be adjusted accordingly. When water quality standards have been achieved, the reach will be moved to the appropriate category in the State's CWA §303(d)/§305(b) Integrated Report.

The Watershed Protection Section will continue to work with watershed groups to develop Watershed-Based Plans to implement strategies that attempt to correct the water quality impairments detailed in this document.  Implementation of items detailed in the Watershed-Based Plans will be done with participation of all interested and affected parties.

A TMDL is a planning document that establishes specific goals to meet water quality standards in waterbodies where pollutant limits are exceeded. It includes current pollution loadings, reduction estimates for pollutants, information on probable sources of pollution, and suggestions to restore or protect the health of the waterbody.

For more information, please contact Heidi Henderson at the address or phone number provided above.


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