Water Quality and Hydrology

The hydrologic cycle describes movement of water on earth. Some of the processes by which water moves include: precipitation, infiltration (soil moisture and groundwater), and streamflow. In order to account for the distribution of water within a specific area, it is necessary to consider these processes. One of the units used to quantify and analyze water and its effects at a specific location is the watershed. A watershed, or drainage basin, is an area of land in which all water within drains to the same outlet. The five WFRC counties fall within three major watersheds terminating at the Great Salt Lake; Weber River, Jordan River, and Great Salt Lake watershed (Tooele County). Each major watershed has a hydrologic system of intermittent streams, perennial streams, rivers, and waterbodies delivering water from the highest slopes of the Wasatch Range to the Great Salt Lake.

In terms of defining local hydrologic systems, spatial datasets from the United States Geological Survey (USGS) like the National Hydrography Dataset (NHD) and the Watershed Boundary Dataset (WBD) are used to determine the location of watershed boundaries and surface water (rivers, lakes, and springs) in the United States.

Winter and spring snowfall is the principle source of surface water in this region. [1] Annual melting of high-elevation snowpack creates water runoff flows to refill reservoirs and recharge groundwater aquifers. Spring peak flows also support sediment transport, channel maintenance, and riparian vegetation. Spring rains provide a minor contribution to reservoir storage but are primarily important for postponing the timing of reservoir water use. Although thunderstorms may add flow, low flows or dry conditions generally occur in the late summer, which results in many water quality issues.

The US Climate Data website to provide tabular annual climate data for most Utah cities. Regional climate information is produced by Oregon State University through PRISM, which provides spatial data to map 30-Year Normal (1981-2010) precipitation, temperature, and other climate information. Stream gauges are also useful for instantaneous and historic river flow rates.

As surface water enters and moves through a watershed, some portion of the water infiltrates into the ground and recharges aquifers. Groundwater enters aquifers through primary and secondary infiltration zones and naturally exits at discharge zones. Groundwater discharge at seeps and springs supports aquatic habitat and provides important stream input during dry months. Summer base flows are very important for aquatic species and support habitat for a wide variety of common and rare wildlife.[2] Groundwater pumped from aquifers is also a critical resource for culinary and agricultural water supplies.

Watershed boundary data (HU for Hydrological Unit) can be combined with the Annual Precipitation data to get an idea of the amount of water each watershed receives annually. The National Hydrology Datasets (NHD) of Flowline data, Waterbody data, Point data, etc. can be used to understand the path water travels in a watershed.

The Utah Geological Survey (UGS) provides an aquifer data layer to aid groundwater studies by identifying generalized zones of recharge and discharge within various basins of the State. The data is compiled from previous studies and includes much of the urbanized portions of the WFRC planning region.

The groundwater program at UGS has many other technical reports, maps, and articles available regarding groundwater resources and springs in Utah that will be useful for county planners. The UGS groundwater program develops maps of groundwater resources under contracts with local governments. Reports and maps from these studies are available on the groundwater program website or by purchase on CD-ROM. Other county specific reports are available for download from the USGS Publications Warehouse.

Land use change and river channelization are two more components of hydrology pertinent to resource management plans. The landscape within the region is changing from rural to urban due to population growth and human development. As dominant land use transitions to urban, the total area of impervious surface increases. As farms and wildlands are converted into houses, roads, and other hard surfaces, water is prevented from infiltrating into the ground. This hardening of the landscape results in more water flowing overland during storm events and “flashier” stream responses with higher peak flows and shorter durations. To facilitate these flood events, natural riverways are often channelized and hardened resulting in changes to the natural river channel which affect riparian vegetation, wildlife habitat, and aquatic habitat.

Another consideration for the WFRC region is that the hydrology supplying water to the Great Salt Lake has changed tremendously over the last 150 years, which has resulted in significant changes to the lake. These hydrologic changes are driven by transitions in land use and affect both water quality and quantity entering the lake.[3] Among other efforts, the Great Salt Lake Advisory Council, Utah Division of Forestry, Fire, and State Lands, and other entities are developing an integrated water resource model to better forecast lake levels.

In Utah, water quality is regulated by the state based on the source of pollutants entering waterways, defined as either “point source” or “nonpoint source” pollution. Point sources (PS) discharge pollutants directly into a waterbody, usually through pipes or ditches originating from industries or waste treatment plants. Nonpoint sources (NPS) are pollution sources that do not originate from distinct locations and tend to vary in time and space. Nonpoint source pollution occurs when runoff from rainfall or snowmelt picks up pollutants from the human and natural landscape and transports them indirectly to a waterbody.

There are several datasets (Monitoring Sites, Gage sites, Assessment units, etc.) that the county can use to understand where and how water quality is monitored.

Common water quality characteristics include:

• Conductivity. A measure of the ability of water to conduct an electrical current. It is dependent on the amount of dissolved solids in the water.
• Dissolved oxygen. A measure of the amount of oxygen dissolved in water. Water’s capacity to carry dissolved oxygen (DO) is inversely related to temperature; as temperature increases, DO decreases. Fish and other aquatic organisms require DO respiration. If dissolved oxygen levels are too low, populations of aquatic organisms can be severely impacted.
• Nutrients. Nutrients such as Nitrogen (N) and Phosphorus (P) are essential for plant and animal growth and nourishment. However, excessive nutrients from human sources become problematic when they over accumulate and can cause adverse effects within waterbodies. Nutrient-fed algal blooms can consume oxygen used by other aquatic organism, produce toxins which can harm livestock and humans, or contaminate recreational waters.
• pH. A measure of how acidic/basic water is, pH is used as an indicator of chemical changes in the water. As a side note, some streams in Utah tend to have slightly higher pH because of their limestone substrates.
• Suspended sediment. The amount of sediment moving with along with a stream suspended in the water column. This depends partly on water flow; fast-flowing water can move more sediment than slow-flowing water. This measurement also depends on the amount of fine sediments available to transport.
• Water temperature. Changes in water temperature can impact aquatic organisms, as well as humans (e.g., recreational and industrial uses). Water temperature also affects DO—as temperature increases, water’s capacity to dissolve oxygen decreases.  
• Turbidity. A measure of the amount of particulate matter that is suspended in water. Turbidity measures the scattering effect that suspended solids have on light entering the water.

Point Source Pollution

Point source pollution originates from a distinct business, operation, or other specific location. Point source pollutants are highly regulated under the Clean Water Act of 1972 and Water Quality Act of 1987 through the issuance of permits and possible fines if permit requirements are not met.The United State Environmental Protection Agency (EPA) issues discharge permits within the National Pollutant Discharge Elimination System (NPDES). In Utah, the State was granted primacy by EPA to manage the NPDES permitting program as the Utah Pollution Discharge and Elimination System (UPDES) and is operated by the Utah Department of Environmental Quality (DEQ) Division of Water Quality (DWQ).

NPDES permits are required for the following operations and activities:

• Animal feeding operations*
• Industrial wastewater
• Municipal wastewater
• Pesticide applications
• Stormwater
  • Construction activities
  • Industrial activities
  • Municipal and transportation sources
• Forest Roads (pending)

* The Clean Water Act explicitly excludes agricultural runoff and irrigation return flow as point source pollution.

Nonpoint Source Pollution

Nonpoint source pollution originates from a variety of dispersed sources, such as parking lots, roadways, residential landscaping, agricultural operations, stream bank erosion, fire scars, and many other sources. Once mobilized, these pollutants enter streams, waterbodies, wetlands, and groundwater. Because of its complex nature, NPS pollution is not regulated through permitting under the Clean Water Act. Instead, NPS pollution is managed in Utah by the Division of Water Quality through voluntary and incentivized actions of individual landowners. The Water Quality Act requires states to prepare NPS pollution assessment reports and includes provisions for federal funding for implementing NPS management.[4] In some cases local governments have established development codes to compel actions to reduce NPS.

Common NPS pollutants and sources include the following: [5]

• Fertilizers, herbicides, and insecticides from residential and agricultural areas
• Oil, grease, and other toxic chemicals from roadways and parking lots
• Sediment from construction areas and roadways
• Salts from roadways and agricultural areas
• Acid drainage from abandoned mines
• Bacteria and nutrients from septic systems, pet waste, and livestock

Due to the diffuse nature of NPS pollution, the Division of Water Quality uses water quality data in streams and lakes to determine levels of pollution within a watershed. The Utah Division of Environmental Quality collects water quality monitoring data to determine if a waterbody supports its designated beneficial uses and meets water quality standards.

A statewide assessment report, called the Integrated Report, is produced by the Division of Water Quality every other year. This report summarizes overall surface water conditions, estimates the importance of key water quality concerns, identifies impaired waterbodies, and helps agencies prioritize resource needs.[4] This report also helps in the development of Total Maximum Daily Loads (TMDL), which is a calculation of the maximum amount of a pollutant that a waterbody can have while still meeting water quality standards and required for impaired waterbodies. Data for assessed waters in Utah is public and can be found in the Utah Environmental Interactive Map application. Water quality data is divided by waters with no impairments, waters with no evidence of impairment, waters with insufficient data, impaired waters with a TMDL, and impaired waters that need a TMDL.

A hydrological asset network map was also created for the Wasatch front region as part of the Wasatch Front Green Infrastructure Plan in order to protect and enhance water resources by identifying prioritization areas when it comes to management actions and restoration projects. [6]

Other sources of water quality and quantity data include the USGS National Water Information System (NWIS), and other monitoring programs from agencies like NOAA, and the EPA (STORET). The State of Utah stores and manages its own water quality data on the Ambient Water Quality Monitoring System (AWQMS database).