How to review Oregon's Integrated Report
This story map will walk users through Oregon's assessment process for reporting at the assessment unit level
Oregon's Assessment Units
For Oregon's Integrated Report, water quality assessment conclusions are reported at an assessment unit level. Assessment Units are segments of streams/rivers or waterbody areas that are predetermined based on similar hydrology and represent similar environmental/hydrographic characteristics. Assessment Units can vary in size from less than one stream mile to greater than 200 stream miles. Assessment Units are further grouped into five distinct types.
Oregon Assessment Units
Five types of Assessment Units in Oregon
Evaluation of Assessment Units
One assessment unit can have data for over 150 unique parameters, collected from multiple monitoring locations. The DEQ must use a publicly reviewed methodology to determine an assessment conclusion for each parameter.
The overall status of the assessment unit is determined by a hierarchy where any one parameter determined to be not supporting a beneficial use results in an overall impaired water.
Oregon's IR Categories
The way Oregon evaluates and displays assessment conclusions depends on the type of unit.
Specifically, because watershed assessment units can represent multiple small streams within a sub-watershed ( Hydrologic Unit Code 12 ), they are assessed in a different way than the other 4 types.
Reviewing Non-Watershed Assessment Units
For river/stream, waterbodies (lakes, reservoirs and estuaries), coastline and marine assessment units data from individual monitoring locations are pooled to determine parameter categorical assignments.
Let's follow an example for a River/Stream Assessment Unit OR_SR_1707010512_02_101514. There are 6 parameter assessment conclusions based on data collected at two monitoring locations.
The assessment unit is Category 2 (attaining) for biocriteria, Category 3 (insufficient data) for dissolved oxygen, pH and ammonia and Category 4A (impaired but a TMDL has been issued) for temperature (spawning and year round)
To report at the assessment unit level, the individual parameter assessment conclusions are rolled up to overall status following this hierarchy -
Category 5 or 4 (Impaired) > Category 2 (Attaining) > Category 3 (Insufficient Data)
Therefore, because temperature is not meeting water quality criteria set to protect aquatic life, the assessment is classified as impaired.
Flow chart showing how individual parameter assessments are rolled up to an overall assessment unit's status.
Reviewing Watershed Assessment Units
The watershed assessment units are assessed differently than other units. In response to feedback on the 2018/2020 Integrated Report, we have modified how we assess the watershed units to include a more detailed accounting of where impairments exist.
Use Slider to see the additional level of detail now being displayed for watershed assessment units.
For watershed assessment units each monitoring location is evaluated for parameter categorical assignment independently.
Of the two monitoring locations on Reynolds Creek, one is determined to be Category 5 (impaired). Each stream with data within a watershed is assigned an overall status using the same hierarchy this time at the monitoring location level.
Category 5 or 4 (Impaired) > Category 2 (Attaning) > Category 3 (insufficient data)
Therefore, because of the one impaired monitoring location (shown on the map in purple), Reynolds Creek will be displayed as impaired on the IR interactive webmap with a purple dotted line. Whereas, Mossy Gulch will be represented as attaining by the monitoring location symbol of green.
Flowchart to show how parameter categorical assignments at the monitoring location level are rolled up to an individual stream within a watershed assessment unit. The streams are defined by the NHD GNIS_Name.
An overall status of the watershed assessment unit must still be reported. To do this, the same categorical hierarchy is used, this time at the stream or NHD GNIS Name level.
Flowchart showing how parameter categorical assignments for individual streams within a watershed assessment unit are rolled up to an overall status.
How to Provide Comments to DEQ
Comments can be submitted to IntegratedReport@deq.oregon.gov
DEQ will be holding two webinars to walk through updates and conclusions from the draft 2024 Integrated Report and to provide technical assistance for reviewing and providing comments on the report. The webinars will have the same content.
Webinar Information for 2024 draft Integrated Report:
Webinar 1: May 1, 2024 at 10:00 a.m. Register via Zoom
Webinar 2: May 7, 2024 at 6:00 p.m. Register via Zoom
Sign up for future project updates online at: https://public.govdelivery.com/accounts/ORDEQ/subscriber/new?topic_id=ORDEQ_382.
