ScopeofWorkForMMIRecalibration_MIG2025.docx

SCOPE OF WORK

Tasks/Description of work Task 1. Review reference site conditions across geographic divisions. Using GIS-based information, current disturbance gradient, and existing BURP data, the contractor will review reference condition for Idaho streams and rivers as it pertains to macroinvertebrate and fish communities and habitat, and develop/revise new reference conditions as needed. Reference conditions should account for biogeographic differences within Idaho and may use or revise the current ecoregional divisions for streams (PPBV, foothills, and mountains) and rivers (Mountains and non-mountains).

DEQ’s current framework for streams is based on comparison of test sites to regionally identified reference conditions and a disturbance gradient, which measures difference in a site’s condition from those reference conditions. Since the current framework was approved, GIS coverage, natural conditions, and technical capabilities may have changed; DEQ seeks development of a new disturbance gradient using a comparable method to the current one. This trend analysis should provide understanding and insight into conditions at sites in rivers and streams in each geographical grouping, and for each component of the monitoring data.

Contractor will be responsible for determining reference condition based on historical reference data collected from watersheds with minimal human impacts, as identified in historical BURP surveys and verified through GIS data, field observations, and other methods. Contractor will identify proper geographical categorization based on ecoregions, current delineations, or other suitable classification. All determinations should reflect current state of the science for determining ecoregional reference condition and should be based on proper statistical testing. Contractor will work with DEQ project manager and surface water program staff throughout development to make sure that the product will meet DEQ objectives and needs.

Task 2. Revise and/or develop multimetric indices used for assessment of streams and rivers. Contractor will assess performance of current mulitmetric indices, investigate modifications or improvements them and, if necessary, determine component metrics to be used in new multimetric indices based on their ability to best discriminate between reference condition and impairment.

DEQ currently uses three indexes for assessing small streams: the Stream Macroinvertebrate Index (SMI2), Stream Fish Index (SFI2), and Stream Habitat Index (SHI2). Similarly, large rivers are assessed with the River Macroinvertebrate Index (RMI2), and River Fish Index (RFI2).

Contractor will evaluate and revise or develop alternatives to DEQ’s existing Macroinvertebrate, Fish, and Habitat indices for streams and Macroinvertebrate and Fish indices for rivers. Component metrics and their associated indices will be based on their ability to discriminate between reference condition and impaired waters using a disturbance gradient that interprets existing data from DEQ’s Beneficial Use Reconnaissance Program (BURP). Metric selection will be based on best available science and empirical evidence for ability to identify impaired waterbodies. Revised multimetric indices will be peer-reviewed and comments will be addressed in the final product document. Indices will be tested with reserved data from sites that were excluded from use in index development. Contractor will work with DEQ project manager and surface water program staff throughout development to make sure that the product will meet DEQ objectives and needs.

Task 3. Develop predictive model based on physical attributes (i.e., RIVPACS-type, O/E model) for assessing biological communities. Contractor will develop a robust and simple predictive model for macroinvertebrate communities based on readily-determined environmental variables. The model will be based on best available science and must demonstrate successful performance with existing BURP data. Contractor will recommend taxonomic resolution for developing the model based on available literature and empirical evidence from BURP data. The draft model must be operable by DEQ staff, and will be peer-reviewed with comments be addressed in the final product document. Contractor will work with DEQ project manager and surface water program staff throughout development to make sure that the product will meet DEQ objectives and needs. DEQ prefers that the product be provided in the R programming language and requires that the model is compatible with DEQ’s IDASA2 application.

Task 4. Produce framework document detailing the scientific basis for development of the indices and how the framework will be implemented. This will be DEQ’s technical support document describing how to evaluate stream and river data in order to assess aquatic life use support. The document should include discussion of the scientific basis for inclusion of selected metrics, geographic regionalization, and ability of indices to discriminate between reference condition and impairment within regions. This document will be peer-reviewed by mutually agreed reviewers before becoming final.