Nevada Division of Environmental Protection

Nevada Division of Environmental Protection maintains a monitoring program throughout the state, including the Truckee River watershed. Find descriptions of the program at this link: http://truckeeriverinfo.org/project/ndep-truckee-river-monitoring-project.

and the most current dataset is below. Further data may be found in the State's STORET database.

EPA TMDL Case Study, EPA 841-F-94-006, August 1994, Number 13

Documentation of original load allocations of N, P, and TDS as well as one wasteload allocation in the watershed.

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Summary

The objective of our analysis was to develop a biological index for benthic macroinvertebrates for the Nevada portion of the mainstem of the Truckee River using preexisting data. We analyzed data collected by four separate entities, Nevada Division of Environmental Protection (NDEP), Pyramid Lake Paiute Tribe (PLPT), Truckee Meadows Water Reclamation Facility (TMWRF), and Desert Research Institute (DRI). To develop a common dataset from collections of multiple entities, an evaluation of the field and/or lab methodological differences was performed to minimize non-random error. A common index period was designated as low flow (July to October), all replicates were combined, and the number of individuals per sample was set to 500 organisms (samples with more organisms were randomly sampled with a computer to 500).

A multimetric index was developed from the data set and comprised six metrics or attributes of the benthic macroinvertebrate assemblage; total taxa, percent Ephemeroptera, percent Chironomidae, percent dominant taxon, percent filterers, and percent clingers. In an assessment, each metric value is converted to a standard score ranging between 0 and 100 (100 being closest to reference or optimal value). The scores for all six metrics are averaged to obtain an aggregated index score and compared to thresholds or break points based on percentages of the overall score and expected conditions for a good quality benthic macroinvertebrate community. Application of the benthic index to the mainstem of the Truckee River indicated the biological condition was of higher quality in the upper reaches and declined in quality as the river approaches Pyramid Lake. A more definitive assessment is pending the results of the analyses on companion assemblages of the aquatic community, namely the fish and algal assemblages.

Section 303(d) of the Clean Water Act requires states to identify waters that do not or are not expected to meet applicable water quality standards with technology-based controls alone. Once these waters are identified, states are to develop total maximum daily loads (TMDLs) at a level necessary to achieve the applicable water quality standards. The Truckee River at Lockwood is listed on Nevada's 303(d) List for total nitrogen, total phosphorus and total dissolved solids. NDEP has chosen to use the chemical specific approach for the establishing TMDLs.

Section 303(d) of the Clean Water Act requires states implement water quality-based controls where technology based limits and implemented Best Management Practices (BMPs) are not sufficient to achieve water quality standards. A TMDL is a tool for implementing State water quality standards and is based on the relationship between pollutant sources and in-stream water quality conditions. TMDLs integrate the management of both point and nonpoint sources of pollution to a waterbody. The TMDL establishes the allowable loadings or other quantifiable parameters for a waterbody and thereby provides the basis for establishing water quality-based controls. These controls should provide the pollution reduction necessary for a waterbody to meet water quality standards.

A TMDL quantifies pollutant sources and allocates allowable loads to the contributing point and nonpoint sources so that the water quality standards are attained. The greatest amount of loading that a water can receive without violating water quality standards is the loading capacity. The waste load allocation (WLA) is the portion of a receiving water's loading capacity that is allocated to existing or future point sources of pollution. EPA regulations (40 CFR 130.2(g)) provide that load allocations for nonpoint sources and/or natural background "are best estimates of the loading which may range from reasonably accurate estimates to gross allotments...."

This document first describes the methodology used for determining a TMDL for both conservative and nonconservative parameters. Then water quality attainment programs other than waste load allocations in the Truckee Meadows Water Reclamation Facility (formerly known as the Reno/Sparks Wastewater Treatment Facility) NPDES permit are discussed. Finally, TMDLs/WLAs for TDS, TN and TP are discussed including a discussion of the proposed NPDES permit and attainability.

The major streams in Nevada have had TMDLs (Total Maximum Daily Loads) established for several years. However for some of these streams, the TMDLs are expressed as an average daily load based upon average long term flow conditions. These TMDLs have been dubbed as "bare bones" TMDLs due to the simplicity of the calculation and their lack of usefulness. While these TMDLs seem to satisfy the requirements of the Clean Water Act, they have contributed little to any watershed/waterbody assessment and restoration plans. These types of TMDLs do little to characterize the problems the TMDLs are intended to address. Without adequate characterizations, appropriate solutions cannot be identified and implemented.

This point shapefile shows all sample sites from the Nevada Division of Environmental Protection (NDEP) compilation of monitoring stations in the Truckee River Basin. This includes NDEP and Desert Research Institute (DRI) monitoring stations, as well as special study and miscellaneous sites. To view long term monitoring sites and special study sites separately, please refer to Maps and GIS section, titled "NDEP Monitoring Sites and Special Sites map images".

This shapefile is in GCS_North_American_1983 (latitude-longitude), North American Datum of 1983.

This is a polygon shapefile of the waterbodies in the Truckee watershed area. It is a subset of the Nevada Division of Environmental Protection (NDEP) shapefile of Nevada waterbodies.