The MWP is the main discharge zone of the larger Moab-Spanish Valley groundwater and surface water system. Groundwater discharges to the land surface and to the Colorado River. Discharge from springs to the northeast enters the northern part of the Preserve as surface flow and Mill Creek flows along the southern Preserve boundary before entering the Colorado River. The water supply and ecological health of the MWP are, therefore, tied to changes in the larger groundwater and surface-water system. Monitoring spring discharge, tracking wetland health, and calculating the water budget of the MWP will provide important baseline data for evaluating the effects of upgradient changes in water use and delivery and future management strategies.

The overall objective is to provide data to the wetland managers and to local and state water managers that help them ensure the long-term survival of the Preserve. Specific objectives include the following. 1) Evaluate the position, seasonal and long-term fluctuations, and origin of the brine layer that underlies the fresh water which sustains the wetlands. This will include assessing possible changes since previous studies (Gardner, 2004; see below), chemical sampling, and use of Transient Electromagnetic (TEM) resistivity to provide a more detailed map of the top of the brine layer, which to date is poorly constrained. Upward movement of the brine layer as fresh water sources decline could threaten the vegetation health, wildlife habitat, and water quality of the Preserve. 2) Monitor discharge from springs that issue from bedrock aquifers east of the Preserve. The outflow from these springs is an important source of surface water to the Preserve and in the future more water may be diverted for other uses, which would reduce the water supply to the preserve. 3) Monitor surface water inflow to and outflow from the Preserve.  This task will be challenging due to the complex piping/diversion system from the springs to the Preserve. We will map these features and establish monitoring sites to provide a detailed understanding of surface flow dynamics. 4) Evaluate groundwater inflow to the Preserve.  This will involve the study of hydraulic head in existing and, if necessary, new wells and nested piezometers to describe the origin and direction of flow in both the fresh upper valley-fill aquifer and the underlying brine layer, recording possible changes since previous studies (see below), and monitoring future trends in relation to changing upgradient water use in the rest of Spanish Valley. Other new wells will fill in data gaps in the current well system to evaluate groundwater flow and agricultural tailflow into the northern and eastern parts of the Preserve. 5) Evaluate groundwater discharge from the Preserve to refine the water budget by measuring surface flow from the refuge pond to the Colorado River, using existing and new piezometers to determine groundwater flow to the Colorado River, and measuring evapotranspiration directly using an eddy covariance tower. 6) Map out the current distribution of major wetland communities in the MWP and conduct vegetation monitoring in the vicinity of wells and across the boundary of the brine layer. Develop recommendations for long-term vegetation monitoring. The wetland communities and water sources that sustain them are fundamental to the functions and values of the MWP; therefore, these metrics define the health of the preserve and will serve as the barometers for the effects of future changes and management decisions. 7) Assess past change through remote sensing analysis of surface water extent and vegetation health (as measured by NDVI). Remote sensing analysis will allow us to identify stable and changing areas of the MWP, which will provide valuable context about historic changes to the MWP and help us identify key areas for future monitoring. We will also evaluate whether we can track vegetation response to past changes in the brine layer using remote sensing analysis. 8) Evaluate the importance of Colorado River flooding to groundwater levels and wetland health, by 1) combining analysis of past imagery showing surface water extent and NDVI to show the physical extent of past flooding events and the resulting changes in plant health, and 2) establishing monitoring sites to measure the amount and quality of water infiltrated and sediment accumulated during flood events and subsequent changes in vegetation. 9) Establish a long-term monitoring system, focusing on the position of the brine layer, flow of key springs, and wetland health.

Central Pond is a refuge for Razorback Sucker. Potential threat is inadequate water supply to maintain the population.

Quantifying water inputs and outflows, and the subsurface position and movement of the brine layer, will help the Division of Wildlife Resources and The Nature Conservancy manage existing water for maximum habitat benefit, and strategize for possible future changes in water management and/or acquisition of water rights.

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The project is all about quantifying surface flow and groundwater flow in and out of the preserve, and monitoring water quality focusing on the nature and position of the brine layer underlying the preserve.

UGS notifies DWR and TNC prior to conducting field work. We are formulating installation plans for continuous monitoring of surface flow and will collaborate to ensure any necessary permitting is fulfilled. If at a later time we agree to install new monitoring wells, UGS will handle permitting with the Division of Water Rights and Wildlife Resources.

Evaluate Fresh Water-Brine Boundary Task 1. Map subsurface position of brine-fresh water boundary layer and evaluate source waters of brine. Goal: Use existing monitor wells, Transient Electromagnetic Method (TEM) resistivity surveys and, if necessary, chemical sampling and installation of new monitor wells to map the top of the brine layer. Scope of Work: 1. Compile previous work, including well and electrical resistivity data, that constrain the position of the fresh water-brine boundary layer. 2. Construct potentiometric-surface maps of the tops of the fresh water and brine layers. 3. Conduct preliminary TEM surveys to assess data collection parameters. 4. Sample wells to obtain conductivity values of the brine layer to calibrate TEM surveys and evaluate source(s) of the brine layer (Paradox Formation water, groundwater, and Colorado River water are possible components of the brine). 5. Refine the position of the fresh water-brine boundary layer in critical areas (e.g., near Colorado River and Eastern boundary of the wetlands). 6. Establish stations for repeat TEM measurements to track possible fluctuations of the boundary seasonally and over longer time periods. 7. Determine whether current monitor wells provide sufficient control on the position of the fresh water-brine boundary layer. If not, evaluate possible installation of new monitor wells in consultation with project partners. 8. Identify and facilitate long-term, real-time data collection to a repository (UGS, USGS or Water Rights) for the purpose of observing changes in water level elevations for both the brine and freshwater layers in the Preserve. (DWRi believes it is important to establish real-time monitoring stations to measure changes in water level elevations long-term.) Deliverables: Database and GIS maps showing current depth of fresh water-brine boundary layer, changes since the previous electrical survey was conducted, and seasonal fluctuations if measured.  Chemical data on the brine that will help evaluate its origin, including the identity and mixing ratios of contributing sources. Refine Water Budget Task 2. Measure spring flow. Goal: Quantify flow from springs issuing from the Glen Canyon Group aquifer east of the Preserve. Scope of Work: 1. Establish long-term monitoring stations (metering) of Skakel, and Watercress (a.k.a. Moab Springs Ranch) Springs, and Water Park (a.k.a. Duck Puddles) North and South horizontal wells at their sources. Identify and facilitate long-term, real-time data collection to a repository (UGS, USGS or Water Rights) for the purpose of observing changes in spring flow discharge to the Wetlands. (DWRi believes it is important to establish real-time monitoring stations to measure flows long-term.) 2. Conduct geochemical sampling, if necessary, to confirm aquifer source and flow path(s) for spring discharge. 3. Using previous and any new evaluations of spring source and flow path, evaluate potential susceptibility to future climate fluctuations and groundwater pumping. Deliverables: Data and analyses showing discharge from key springs at their sources including possible seasonal variability and changes since the early 2000s. Ranking or other qualitative or quantitative evaluation of spring discharge to likely future hydrologic changes (e.g., climate variability and increased groundwater pumping). Task 3. Measure sources of water to the Preserve. Goal: Characterize the amount, variability, and water quality of surface- water and groundwater flow into the Preserve, focusing on flows that sustain critical habitats. Scope of Work: 1. Measure surface flow into the Preserve, including all of the discharge points from Skakel & Watercress Springs and; Waterpark horizontal well and, possibly shallow piezometers or periodic manual measurements where inflow is diffuse or transient. 2. Identify and establish long-term, real time measurement stations for groundwater discharge into and out of the Central Pond area, including installation of nested piezometers and/or surface flow sites. 3. Evaluate surface water-groundwater connection between Mill Creek and the shallow aquifer underlying the preserve, using existing and/or new piezometers and seepage runs. 4. Refine the estimate of return flow to Mill Creek as identified in the 2019 USGS report using data from the U.S. Geological Survey's surface flow gage 09185100 MILL CREEK BLW PACK CREEK combined with seepage runs. 5. Estimate seepage and direct surface flows from adjacent agricultural areas into the Preserve using new piezometers (if needed) and nitrogen isotopes. If there are any direct surface inflows from the ag areas, installation of long-term, real -time measurement stations may be required. 6. Review historical flood events from the Colorado River into the Preserve for the following purposes: a) to identify and harden (protect) any existing or contemplated infrastructure such as monitoring wells, inlet/outlet structures, pipelines, etc., from damage from such events, b) to develop a plan for evaluating the effects of such flood events on the hydrologic components within the Preserve (i.e. do these event help suppress the brine layer, do they increase water table elevations for significant periods of time after the flood flows have receded (day-weeks-years), do they change water quality to the benefit or detriment of wetland vegetation, etc...). Deliverables:  Revised, site-specific estimates of water inflows to the Preserve and changes since previous studies. Task 4. Estimate water discharge from the Preserve. Goal: Evaluate water discharge from the Preserve, including evapotranspiration, surface flow, and subsurface discharge. Scope of Work: 1. Measure wetland evapotranspiration rates using an eddy-covariance flux station (this work will be mostly funded by a separate grant). 2. Revise estimates of discharge to Colorado River using updated groundwater levels, updated outflows from Mill Creek, and updated outflows from the Central Pond. Deliverables: Revised estimates of water discharge from the Preserve and changes since previous studies. Evaluate Wetlands and Vegetation Task 5. Map Wetlands. Goal: Obtain baseline data on distribution of vegetation and water regimes to help understand water needs for the Preserve, provide context for hydrologic data, and obtain vegetation data to support remote sensing analysis. Scope of Work: 1. Collect high resolution aerial imagery of Preserve near peak flows on the Colorado River. 2. Collect field data in spring and summer to calibrate and validate mapping. 3. Create a wetland map using manual aerial imagery interpretation. 4. Describe map units in a brief mapping report. Deliverables: Aerial imagery for Preserve and spatial data showing wetland, riparian, and upland areas within Matheson Preserve mapped to National Wetlands Inventory standards, with additional vegetation community information in attributes and mapping report. Task 6. Use Remote Sensing to Monitor Wetland Conditions and Evaluate Past Trends. Goal: Identify spatial distribution of past vegetation and surface water trends in the Preserve and evaluate use of NDVI as a method for evaluating changes in the brine layer over space and time. Scope of Work: 1. Analyze relationship between vegetation data and NDVI values to determine correspondence between NDVI values and vegetation communities. 2. Create NDVI slope and standard deviation map for the Preserve to identify stable, dynamic, and changing areas of the Preserve in terms of NDVI. 3. Divide the Preserve into discrete units based on above raster and major differences in hydrology, vegetation, management, and salinity. Calculate NDVI and surface water extent trends for each unit. 4. Analyze NDVI values with brine layer spatial data to determine extent to which NDVI can be used to track changes in brine layer over time. 5. Develop models predicting surface water extent and NDVI based on factors such as climate, river levels, groundwater levels, and management history. Deliverables: Brief report summarizing results of remote sensing analysis and recommendations for use of remote sensing analysis as a means of monitoring at the Preserve. Task 7. Establish Vegetation Monitoring and Photo Plots. Goal: Obtain vegetation data at locations with hydrologic monitoring to refine understanding of relationships between vegetation and hydrology. Establish vegetation monitoring plots associated with brine layer. Scope of Work: 1. Select initial monitoring locations at existing hydrologic monitoring stations and where the brine layer potentially encroaches on the root zones of key wetland vegetation. 2. Develop study design and field protocol for vegetation monitoring and conduct monitoring. 4. Analyze data to look at relationships between hydrologic monitoring data, surface water levels, vegetation communities, and soil salinity measurements. 5. Write report and develop recommendations for long-term monitoring. Deliverables: Brief report describing results of data analysis. Monitoring data organized into a geospatial database with photographs and survey results. Coordination Meetings Task 8. Hold quarterly coordination meetings with Project Participants. Goal: Maintain close communication with project participants to determine if the "other" work identified in this proposal is necessary and to receive feedback as the study progresses. Scope of Work: 1. Meet quarterly with project participants. Deliverables: Informal quarterly presentations to project participants that encourage conversation about the status of the project.

Task 6. Use Remote Sensing to Monitor Wetland Conditions and Evaluate Past Trends. Goal: Identify spatial distribution of past vegetation and surface water trends in the Preserve and evaluate use of NDVI as a method for evaluating changes in the brine layer over space and time. Scope of Work: 1. Analyze relationship between vegetation data and NDVI values to determine correspondence between NDVI values and vegetation communities. 2. Create NDVI slope and standard deviation map for the Preserve to identify stable, dynamic, and changing areas of the Preserve in terms of NDVI. 3. Divide the Preserve into discrete units based on above raster and major differences in hydrology, vegetation, management, and salinity. Calculate NDVI and surface water extent trends for each unit. 4. Analyze NDVI values with brine layer spatial data to determine extent to which NDVI can be used to track changes in brine layer over time. 5. Develop models predicting surface water extent and NDVI based on factors such as climate, river levels, groundwater levels, and management history. Deliverables: Brief report summarizing results of remote sensing analysis and recommendations for use of remote sensing analysis as a means of monitoring at the Preserve. Task 7. Establish Vegetation Monitoring and Photo Plots. Goal: Obtain vegetation data at locations with hydrologic monitoring to refine understanding of relationships between vegetation and hydrology. Establish vegetation monitoring plots associated with brine layer. Scope of Work: 1. Select initial monitoring locations at existing hydrologic monitoring stations and where the brine layer potentially encroaches on the root zones of key wetland vegetation. 2. Develop study design and field protocol for vegetation monitoring and conduct monitoring. 4. Analyze data to look at relationships between hydrologic monitoring data, surface water levels, vegetation communities, and soil salinity measurements. 5. Write report and develop recommendations for long-term monitoring. Deliverables: Brief report describing results of data analysis. Monitoring data organized into a geospatial database with photographs and survey results.

Utah Division of Wildlife Resource The Nature Conservancy Utah Division of Water Rights Utah Geological Survey

Our goal is to provide data for design of long-term, sustainable water management.

Our goal is to provide data for design of long-term, sustainable water management.

07/01/2021

06/30/2022

2022

This grant supports ongoing work to develop a water budget for the Matheson Wetlands Preserve (MWP) and study the brine that underlies fresh groundwater below the MWP. The study is taking place in the MWP and at four locations east of the Preserve and Hwy 191. Final methods include: 1) Monthly or more frequent field visits to measure flow and water levels, as well as repair and calibrate flow meters and pressure transducers; 2) Bi-annual Transient Electromagnetic (TEM) surveys; 3) Two electromagnetic-induction logging surveys to locate the brine-fresh water interface in monitor wells; 4) Water chemistry analyses; 5) Vegetation mapping; 6) Analysis of satellite data to track historical changes in vegetation health using Normalized Difference Vegetation Index (NDVI); 7) Data processing, compilation, and reporting.

We have established a flow measuring routine that captures the volume of water being added to the MWP by two springs, two horizontal wells, and stormwater. It also measures how much water is flowing into the central pond and helps to constrain the interactions between Mill Creek and groundwater. We installed a stilling well near the Central Pond that will help us to calculate the volume of water stored in the pond and the volume released when the pond's control structure is open. We placed an eddy covariance tower in the preserve to measure evapotranspiration in the wetlands. We are monitoring groundwater levels in numerous wells across the wetland. We have placed pressure transducers, logging hourly, in 19 wells in the Preserve and one at Swanny Park, located east of the MWP. Eight of the transducers are also measuring specific conductivity, helping us to observe changes in the brine layer. Two TEM surveys have been conducted, helping to constrain the location of the brine layer. The U.S. Geological Survey conducted electromagnetic induction (EMI) logging of seven wells, which will be used to further constrain the subsurface position of the brine layer and calibrate the TEM surveys. Spatial analysis of groundwater data to construct potentiometric surface maps has begun and will continue throughout the project. The vegetation mapping and NDVI analysis will be conducted during summer 2022. Vegetation monitoring and photo plots will also be established.

Continued monitoring: monthly flow and groundwater monitoring; TEM surveys fall 2022 and spring 2023; an EMI survey fall 2022; NDVI analysis; continued work with Moab City and others to establish a method for monitoring flow of Skakel spring, including the portion of water delivered to the MWP. Groundwater chemistry analyses will be performed to determine groundwater sources, quality, and the origin of the brine. We are conducting quarterly status updates with our project partners, the Division of Wildlife Resources, Division of Water Rights, and The Nature Conservancy. Monitoring is expected to continue in the Preserve until the end of June 2023, at which time efforts will switch to data analysis and report writing. The report is expected to be published June 2024. It will include our findings, as well as suggestions for continued monitoring.