Assess the Montgomery and Newburgh Pool Assessment here. Access all ORSANCO’s Pool Assessments here.
ORSANCO’s biological programs provide critical insight into the health of the Ohio River and its tributaries through long-term monitoring of fish, macroinvertebrates, aquatic vegetation, and habitat conditions. ORSANCO’s recent assessments documented healthy biological conditions in multiple Ohio River pools and demonstrated continued progress in survey methods and basin-wide monitoring. Ohio River pools are sections of the river created by a system of U.S Army Corps dams to maintain sufficient depth for commercial navigation, effectively forming a series of lakes or “pools” with specific pools having distinct characteristics, depths, and surrounding land uses. There are 21 pools in the Ohio River.
In 2024, ORSANCO updated its probabilistic macroinvertebrate survey protocol by deploying two Hester-Dendy (HD) samplers at each site, replacing the previous backup multihabitat sampling approach. The updated method proved effective, with successful retrieval at all sites, improving data consistency, reducing data gaps, and minimizing the need for resampling.
2024 Pool Assessments and Key Findings
During 2024, ORSANCO biologists sampled 30 sites across two Ohio River pools, completing 30 fish surveys and 45 macroinvertebrate collections. Results from both pools indicate overall healthy biological conditions.
Montgomery Pool (Upper Ohio River)
The Montgomery Pool, located near Pittsburgh, Pennsylvania, was assessed in late summer and fall. A total of 3,265 fish representing 43 species were recorded. The fish community was rated Fair, dominated by minnows (38.8%) and sunfish/bass (21.8%). Macroinvertebrates were rated Good, with midge larvae (32.9%), snails (14.5%), and diverse caddisfly, dragonfly, and damselfly larvae present. Notable findings included the rediscovery of the Longhead Darter, numerous young-of-year River and Smallmouth Redhorses, and widespread invasive aquatic vegetation (Hydrilla verticillata).
Newburgh Pool (Lower Ohio River)
The Newburgh Pool, located along the Indiana–Kentucky state line, was assessed during the 2024 cycle. Sampling documented 2,895 fish representing 44 species. The fish community was rated Good, dominated by minnows (34.7%) and herring/shad (28.4%). Macroinvertebrates were also rated Good, with midge larvae (32.3%) and caddisfly larvae (23.0%).
Notable findings included species of concern such as Black Buffalo and River Redhorse, as well as the presence of invasive silver and bighead carp.
Consistent Measures of River Health
All pool assessments were evaluated using the Modified Ohio River Fish Index (mORFin) and the Ohio River Macroinvertebrate Index (ORMin). These tools provide a consistent measure of aquatic health across all 15 navigational pools and support compliance with aquatic life standards under the Clean Water Act.
Basin-Wide Monitoring and Next Steps
ORSANCO also participated in the 2023–2024 National Rivers and Streams Assessment (NRSA), sampling more than 40,000 fish from 152 species across four states. In 2025, biological staff assessed the Racine and Willow Island Pools, with additional focus on the Cannelton Pool, using ORSANCO’s updated survey protocols to continue tracking aquatic health across the Ohio River Basin. Results will be available in 2026.
In 2025, proposed fish tissue consumption advisories were delivered to the states, and work is underway to make PFAS fish tissue data publicly accessible online. Additional fish tissue sampling began in July 2025, with results expected in 2026.
Access the summaries and the full Pool Assessments below: