Ecologically sensitive aquatic insects -- including species of stoneflies, mayflies, and caddisflies -- have declined worldwide. Such declines are concerning because aquatic insects represent the core of freshwater biodiversity, are integral to food-webs, and support economically important fisheries. Further, aquatic insects are biological indicators used to detect water quality deficiencies. Despite known water quality impairments and anecdotal evidence of aquatic insect declines in the Odgen River Basin, little is known about how aquatic-insect communities have changed, and we lack robust, standardized, baseline data necessary for future comparisons. Filling these knowledge gaps will assist resource managers to assess the status and trends of stream health, to integrate insects more effectively into management and restoration planning, and to make more informed contemporary and future decisions regarding resource use within the watershed. To fill these knowledge gaps and, ultimately, to better protect the water quality and biodiversity of the Basin, we propose to quantify macroinvertebrate densities at 14 sites within the Ogden River Basin (supplemental figure 1). Data will be used to calculate biodiversity and the conservation status and distributions of a vulnerable species such as the giant salmonfly [Pteronarcys californica], which has anecdotally been described as declining. We will compare metrics to those measured historically from 1996--2017 (available via the National Aquatic Monitoring Center) to quantify trends in macroinvertebrate and water quality data. Outputs will also be used as a contemporary baseline for future comparison during massive anthropogenic growth and land-use changes that are expected to occur over the next one to three decades within the Basin. This work is imperative to characterize current stream health and to provide scientifically defensible, standardized, and robust data to guide management decisions. Providing more data on sensitive species, including the giant salmonfly will be particularly impactful. The giant salmonfly is one of the largest of all stream insects and draws unapparelled attention from both fishes, terrestrial insectivores, and anglers during its late spring emergences. Salmonflies are a keystone species given their role in cycling nutrients by shredding leaves. However, the giant salmonfly is being considered for inclusion as a Species of Greatest Conservation Need in the 2025 Utah Wildlife Action Plan due to widespread populations declines. The giant salmonfly has disappeared from much of the nearby Provo River and from all of the Logan River. Anecdotal evidence suggests that it is also declining in the Ogden River Basin. However, additional data is needed to confirm these claims and to describe the extent and severity of potential declines. If sensitive taxa are declining, it suggests that local water quality is impaired. Once improved data has been gathered on the status and trends of sensitive species, resource managers will be better able to create conservation and restoration plans to protect and enhance local biodiversity and water quality. This will be of benefit to other at-risk species in the Ogden River and/or in the larger Weber River Basin such as Bonneville cutthroat trout and green sucker. Additional macroinvertebrate data will also facilitate improvements in future resource management during anthropogenic development in the Ogden River Basin. Watershed threats and impairments are already significant within the Ogden River Basin and were recently summarized in the Ogden River Basin Watershed Plan (2023). Impaired waters include the Middle Fork Ogden River (Dissolved Oxygen), South Fork Ogden River (Nutrient/Eutrophication Biological Indicators), and Pineview Reservoir (Temperature, Dissolved Oxygen, Total Phosphorus, and pH). The presence of these impairments in upstream portions of the watershed suggests that downstream locations in the Ogden River Basin, such as the mainstem Ogden River, may also be experiencing adverse effects. Further, rapid, ongoing human development raises concern about other potential impairments, such as increased municipal water demand. Indeed, chronic dewatering is known to occur in portions of the North Fork Ogden, the Middle Fork Ogden, and the South Fork Ogden Rivers and will be worsened by additional withdrawals related to municipal development including those proposed on the South Fork Ogden River (see the Ogden Valley Water Supply and Infrastructure Study [2023], which projects the total number of water connections to grow from near 3,000 in 2012 to over 13,000 in 2060).

This project has three primary objectives: 1) Characterize changes in macroinvertebrate communities, biodiversity, and stream health; 2) determine status of a vulnerable species, such as the giant salmonfly, across the Ogden River Basin; and 3) provide contemporary baseline data that is robust, standardized, and scientifically defensible for future comparisons. Ultimately, these objectives will facilitate better resource management across the Ogden River Basin by providing information necessary for integrating insects into local management and restoration planning and for improving knowledge regarding the status and trends of river health required for making informed contemporary and future management decisions.

This project is important in the Ogden River Basin now because the area is experiencing rapid anthropogenic growth, land use changes, and already has impaired water quality. Additionally, anecdotal accounts suggest a decline in sensitive species including the giant salmonfly, and there are other at-risk species (Bonneville cutthroat trout and green sucker) that may be affected by changes in water quality in or downstream of the Ogden River. Therefore, it is imperative to not only detect current deficiencies in water quality that may lead to species extirpations but also to provide robust, standardized, baseline data necessary for future comparisons.

The UWAP is undergoing a comprehensive revision with a target date of fall 2025 for its completion, and the giant salmonfly is being considered for inclusion as a Species of Greatest Conservation need in the 2025 plan. This project will help to inform distribution of giant salmonflies in the Ogden River Basin. Additionally, there is a TMDL for Pineview Reservoir that indicates that water-quality sampling should be done on its tributary streams to better inform efforts to improve water quality. Lastly, the Ogden River 9-Element Watershed Plan recommends continued monitoring in the Ogden River Basin. This project will provide contemporary baseline data that is robust, standardized, and scientifically defensible for future comparisons.

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This project will help to inform water quality needs and future quality improvements; however, it will not have measurable improvements prior to being used to inform management and restoration efforts. For this reason, the data collected, and any resulting reports, will be made publicly available so that resource managers and restoration practitioners can access contemporary data and water quality information.

We are unaware of any compliance requirements that would pertain to this project. Prior to starting work, we will verify if any scientific-collection permits are needed and obtain any permits deemed necessary.

To complete these objectives, we will collect quantifiable macroinvertebrate samples at 14 riffled sites across the Ogden River Basin -- four sites on the mainstem and South Fork and three sites on the North and Middle Forks. Most sites have been previously sampled by historic, quantifiable macroinvertebrate surveys, which will facilitate temporal comparisons. Previously unsampled sites will be sampled on North Fork Ogden and Middle Fork Ogden rivers to improve distribution of sampling locations in the Basin (supplemental figure 1). At each site, Utah DWQ methods (see Standard Operating Procedure for Aquatic Benthic Macroinvertebrate Collection in Streams Version 2.1 [2023]) will be used, and two composite samples consisting of 8 subsamples each will be collected. Collections will be made using modified Surber samplers from 8 randomly selected riffle locations. Samples will be preserved in ethanol, and invertebrates will be identified and enumerated by taxonomists at StagBenthics, Montana. We will then use the resulting data to assess the current health of the streams and to measure temporal changes, using historical data as a baseline. Response variables used in our assessments and comparisons will include outputs from the River Invertebrate Prediction And Classification System (RIVPACS). RIVPACS is a widely-used, multivariate predictive model that incorporates observed versus expected benthic macroinvertebrate data to detect and quantify anthropogenic stress on aquatic communities of streams and rivers. For example, Utah DWQ uses RIVPACS to compare observed species occurrence with expected species occurrence (i.e., O/E) to monitor stream health across the State. Comparisons will also be made between historical and contemporary biodiversity (e.g., Shannon diversity, richness) and functional metrics, (e.g., percent fauna within functional feeding groups), other water quality metrics (e.g., percent EPT), and densities and distributions of sensitive species such as the giant salmonfly. A final report will be completed to detail our findings, including conservation recommendations, and the report and data will be submitted to an open access repository.

This project is a monitoring project in nature and the final reporting and data will be the primary deliverable.

Trout Unlimited and The Salmonfly Project are partnering to complete this project. Trout Unlimited will provide volunteers and staff time to complete grant management tasks and assist with sampling, data analysis, and reporting. The Salmonfly Project will provide staff time to complete study design and methodology tasks and assist with, sampling, data analysis, and reporting. StagBenthic will complete the taxonomy necessary to identify and enumerate macroinvertebrates and characterize macroinvertebrate communities. Utah DWR, Utah DWQ, the Weber Basin Partnership, and the Weber Basin Watershed Council will all be briefed on study design plans and the draft report. Then, stakeholder and partner input will be addressed prior to final reporting. Staff from Utah DWQ have offered to assist with sampling methodology including in-field assistance where possible.

This project will help to inform water quality needs and future restoration efforts. The data collected and any resulting reports will be made publicly available. To ensure that future restoration practitioners and natural resource managers can incorporate the data and findings in their efforts in the Ogden River Basin.

Understanding water quality deficiencies throughout the basin is the first step in improving natural resources associated with the waterways. Using macroinvertebrate samples to detect water-quality degradation may be more useful for characterizing watershed-level needs than water chemistry samples because changes in macroinvertebrate communities can elucidate long-term trends, while water-quality samples represent snapshots in time (i.e., the moment samples are taken).