Following an AIM-NAMF pilot study in 2011-2012, UTBLM successfully used the AIM-NAMF data to establish quantitative baseline conditions and draw preliminary conclusions regarding which land health standards are potentially not being met. From the data UTBLM identified that water quality exceedances were problematic in specific geographic areas of the State and that more intensive monitoring was required to determine if the water quality exceedances were persistent over time, and if BLM permitted activities contribute to observed exceedances. The need for more intensive monitoring led to an ongoing collaborative effort between UTBLM and Utah Division of Water Quality (UDWQ), which is reducing UTBLM monitoring costs and allowing the UTBLM to leverage data being collected by the State.
In 2011 and 2012, Utah BLM (UTBLM) conducted stream and river monitoring to quantify baseline conditions and identify priority stressors throughout the state. The main objectives of this project were to pilot AIM-National Aquatic Monitoring Framework (NAMF) methods and determine if streams and rivers were meeting aquatic Land Health Standards (as required by 43 CFR 4180.1). Among other requirements, UTBLM Land Heath Standards (LHS) require that rivers and streams meet water quality standards established by the State of Utah (R.317-2), Clean Water Act (33 U.S.C. § 1151, 1251-1387), Safe Drinking Water Act (42 U.S.C § 300f), and the Colorado River Basin Salinity Control Act (PL 93-320).
One of the most salient findings was that water quality exceedances were pervasive throughout the state; with between 48% and 64% of BLM stream km exhibiting excess nutrient and/or salinity (measured as electrical conductivity) loads. Excess nutrients and salinity were most problematic in the Green River District (GRD), where 70% of stream km significantly departed from reference. A subsequent analysis revealed that land uses such as oil and gas development, agriculture, and hydrological alterations were strongly correlated with water quality exceedances, especially excess salinity. These results prompted the UTBLM to intensify water quality monitoring in the Green River District to determine the temporal persistence of water quality exceedances and the extent to which BLM was contributing to the potential problem.
Since water quality condition assessments for the 2011-2012 data were based on one-time measurements taken during base flow, further sampling was required to determine if the water quality exceedances observed in the GRD were persistent over time, related to BLM permitted activities, and sufficient to trigger management action.
In 2016, intensive water quality monitoring began in the GRD. The objectives of this project are to determine which streams and rivers in the GRD consistently fail to meet water quality land health standards, and if adaptive management is necessary to improve water quality.
Figure 1. Map of the Green River District in Utah displaying land ownership, perennial streams and water quality monitoring locations established in partnership with the Utah Division of Water Quality during the 2017 water year.
Site Selection and Study Design
To meet the objectives of this project, UTBLM partnered with the Utah Division of Water Quality (UDWQ) to collect monthly water samples at 31 sites for one year (Figure 1). As part of this partnership, UDWQ is analyzing the samples at no cost to the BLM and collecting additional samples at a network of sites on non-BLM lands. The UDWQ had previously established sample sites at many of the locations that were of interest to the UTBLM so whenever possible, these sites were chosen for monitoring, although several new sites were also established.
In general, sites are located at the upstream and downstream end of BLM-managed lands to determine the extent to which water quality exceedances, if observed, are related to BLM management activities. Data is being collected following both the AIM-NAMF core methods and the standard UDWQ methods to ensure compatibility to between AIM and UDWQ data. The UDWQ is also monitoring several sites in locations for which data will be used to meet the objectives of this project.
Monitoring Objectives and Indicator Selection
The majority of monitoring objectives for this project are closely tied to UTBLM Land Health Standards, however a few additional objectives have been added to help the UDWQ meet their monitoring requirements. The monitoring objectives for this project are as follows:
- Determine if 90% of measured Electrical Conductivity values are below the allowable limits established the Colorado River Basin Salinity Control Act.
- Determine if 90% of samples have a pH between 6.5 and 9.
- Determine if maximum daily temperatures are below allowable thresholds set for the designated beneficial use of the stream segment 90% of the time from June-August.
- Determine if 80% of samples have TN concentrations within 52 µg/L of predicted natural conditions.
- Determine if 80% of samples have TP concentrations are within 10 µg/L of predicted natural conditions.
- Determine if 90% of samples contain less than 1200 mg/L TDS (or other value if site-specific criteria are available).
- Determine if more than 1 sample per site exceed the allowable limits for other chemical constituents being analyzed based on the designated beneficial use of the stream segment.
- Determine the extent to which water quality is being impacted by BLM permitted activities.
Indicators being used to assess attainment of monitoring objectives
The indicators being used to assess attainment of the monitoring objectives are shown in table 1. Note that not all of the AIM-NAMF indicators are being collected since previous water quality exceedances were flagged during sampling events where a complete set of AIM-NAMF data was collected. In addition, several supplemental indicators were included to assess the full complement of water quality constituents regulated by UDWQ.
Table 1. Indicators and condition determination methods used to assess attainment of land health standards related to water quality in the Green River District of Utah.
|Indicator||AIM-NAMF Indicator Status||Monitoring frequency and method||Condition Determination|
|Electrical Conductivity (salinity)||Core||Monthly for 1 year
|Predicted natural conditions
(Olson and Hawkins 2012)
|pH||Core||Monthly for 1 year
|UT State Water Quality Standards (determined by UDWQ)|
|Temperature||Core (instantaneous) and contingent (seasonal)||Hourly during the summer months
|UT State Water Quality Standards (determined by UDWQ)|
|Total Nitrogen (TN)||Contingent||Monthly for 1 year (filtered and unfiltered)||Predicted natural conditions
(Olson and Hawkins 2013)
|Total Phosphorous (TP)||Contingent||Monthly for 1 year (filtered and unfiltered)||Predicted natural conditions
(Olson and Hawkins 2013)
|Total Dissolved Solids (TDS)||Supplemental -required by UDWQ||Monthly for 1 year (filtered sample)||UT State Water Quality Standards (determined by UDWQ)|
|Other constituents (e.g. metals, chlorine, sulfate)||Supplemental – as required by required by UDWQ||Monthly for 1 year (filtered sample)||UT State Water Quality Standards (determined by UDWQ)|
Making Condition Determinations
Water quality condition determinations are made by comparing observed parameter values to state and federal standards, and/or Predicted natural conditions (Table 1). Where available, the use of state and federal standards are required, but when such standards are not available other means are used. In Utah, numeric criteria are not yet available for TN and TP, and therefore predictive models are used to make condition determinations for these indicators.
One of the most accurate ways to determine standards when not set by state or federal regulations is to use models which generate site-specific predictions of the conditions that should occur at a site in the absence of anthropogenic impacts. Such models are developed to explain spatial variability among a set of minimally impacted reference sites using variables related to climate, geology, vegetation, topography, etc. The models are then used to predict conditions expected to occur at a new sample site in the absence of anthropogenic impairment, and the model predictions are compared to the observed values for the site to obtain a measurement of the degree of anthropogenic
For the majority of indicators, UT water quality standards are based on the beneficial use class for individual river and stream segments. Therefore, several condition determination benchmarks are closely tied the beneficial use class designated for the segment of river or stream being monitored. The protected beneficial uses in the State of Utah are as follows: human consumption, recreation and aesthetics, aquatic life and agriculture. The most common beneficial use classes for the locations being monitored are: 2B – infrequent primary contact recreation (e.g. swimming) and secondary contact recreation (e.g. fishing), 3A – cold water game fish and aquatic life, 3C – nongame fish and other aquatic life, and 4 – agricultural uses (e.g. irrigation of crops and stock watering). Designated beneficial uses for each stream and river segment, as well as the numeric criterial for each parameter can be found in UAC R317-2.
This collaborative project began in October 2017 and the next steps are to:
- Sample monthly throughout the 2017 water year
- Identify the most problematic indicators and associated variability throughout the year of sampling
- Determine if water quality is being impaired by upstream users before a river or stream flows through BLM land and establish partnerships with upstream users to try to improve water quality where necessary
- Identify land uses consistently associated with water quality exceedances, and determine the extent to which BLM permitted activities are contributing to impairments
- Develop a prioritized list of locations to potentially target for adaptive management to improve water quality