This basin contains the Borough of Oswayo and land use in the valley of the main stem is mostly agriculture and residential. The surrounding hillsides are mostly forested. Most of the candidate basin is privately owned. Extensive wetland areas are located in the floodplain of Oswayo Creek below Brizzee Hollow. The wetlands are a mixture of forested swamp, shrub swamp, and emergent marsh.

Surface Water:

No long term water quality data were available to allow a direct comparison to water quality criteria. Grab samples were taken at 7 stations throughout the watershed (Figure 1, Table 1). The grab sample results generally reflect good water quality except for alkalinities which were consistently less than 20 mg/l (Table 2). This indicates a very limited buffering capacity and probably results from natural conditions. No direct comparison to applicable water quality criteria can be made, however, due to the instantaneous nature of the samples. The indigenous aquatic community is a better indicator of long term conditions and is used as a measure of ecological significance.

There is one NPDES permitted discharge in the candidate basin. That facility is the fish culture station operated by the PFBC. The NPDES number is 0039144, with a permitted flow of 3.5 million gallons/day (mgd) and an actual flow, based on an average over a six month period in 1996, of 2.9 mgd. The estimated Q7-10 of Oswayo Creek at the point of the discharge is 1.2 mgd.

Aquatic Biota:

Overall habitat scores for aquatic biota fell into the Optimal or Suboptimal categories (Table 3). Instream habitat was generally good but poor riparian zone and bank conditions resulted in Suboptimal overall scores at some sampling stations.

Benthic macroinvertebrate samples were collected at 5 stations during the November 1996 survey. The results of these sampling efforts are presented in Table 4. Benthic macroinvertebrates were collected using sampling techniques adapted from the EPA Rapid Bioassessment Protocols. Taxonomic diversity was uneven. The three stations from the uppermost portion of the basin had a mean of 13 total taxa per station. This probably results from low flow during dry conditions. The remaining stations had a mean of 36.5 total taxa per station, including several genera that are considered sensitive to water quality degradation.

A total of 28 species of fish were collected at three stations (Table 5). Wild brown trout were present at all stations. Other species such as creek chub, redside dace, mottled sculpin, and burbot indicate that cold water conditions occur year round. Streams within the candidate basin support all designated uses.

There are no known portions of the Oswayo Creek basin which qualify as outstanding national, state, regional, or local resource waters under the Department’s regulatory criteria.

Following EPA methodology, a subsample was randomly selected from the macroinvertebrate samples (Table 6). Selected benthic macroinvertebrate community metrics derived from these subsamples were compared to reference stations in the same ecoregion with comparable drainage areas (Table 7). Stations 1OC, 2BH, and 3HH were compared to Nelson Branch Hammersley Fork (R2) and Stations 6OC and 11OC were compared to Hammersley Fork (R3). All of the candidate and reference stations are located in the Unglaciated Allegheny High Plateau subecoregion. See Table 1 for more details on the exact location of each reference station. These reference streams are currently designated Exceptional Value (EV) in Chapter 93. All sampling was conducted over a three week period to minimize the effects of seasonal variation. This comparison was done using the following metrics which were selected as being indicative of community health: taxa richness; modified EPT index (total number of intolerant Ephemeroptera, Plecoptera, and Trichoptera taxa); modified Hilsenhoff Biotic Index; percent dominant taxon; and percent modified mayflies.

Based on these five metrics, all of the stations in the candidate basin had Biological Condition Scores that did not meet the regulatory threshold of 83% of the reference station score required for redesignation to HQ-CWF.

Data from the Pennsylvania Natural Diversity Inventory (PNDI) and the PFBC document the presence of three aquatic species of special concern in the candidate basin. Both Ohio lamprey (Ichthyomyzon bdellium) and burbot (Lota lota) were collected in 1996 at several stations in Oswayo Creek. There is also a 1977 record of Mountain brook lamprey (Ichthyomyzon greeleyi) from the same area. Burbot and Mountain brook lamprey are classified as Pennsylvania Endangered and Threatened respectively. Ohio brook lamprey is listed as a Candidate species

The main stem of Oswayo Creek from the lower property line of the PFBC fish culture station (approximately RMI 27.0) to Clara Creek is classified by the PFBC as a "Class A" Wild Trout Water. The "Class A" classification was subject to public notice and comment by the PFBC. This designation includes 5.5 stream miles.

The Department provided public notice of this redesignation evaluation to and requested any technical data from the general public through publication in the Pennsylvania Bulletin on December 25, 1999 (29 Pa.B 6524). A similar notice was also published in the Olean Times Herald (NY) on December 27, 1999. In addition, Alleghany, Clara, Genesee, Hebron, Oswayo, and Sharon Townships and Oswayo Borough were all notified of the evaluation in a letter dated December 23, 1999. The Potter County Planning Commission was also notified at the same time. No data on water chemistry, instream habitat, or the aquatic community were received in response to these notifications.

The Department sent copies of the draft stream evaluation report to Alleghany, Clara, Genesee, Hebron, and Sharon Townships, Oswayo Borough, and Potter County Planning Commission on May 19, 2000 requesting any comments by June 23, 2000. No comments were received during that period.

Based on applicable regulatory criteria, the Department recommends the following designations:

Oswayo Creek basin (Source to Brizzee Hollow)
- retain current CWF designation

Brizzee Hollow basin (source to mouth)
- retain current HQ-CWF designation

Oswayo Creek basin (Brizzee Hollow to Clara Creek, except South Branch Oswayo Creek)
- change current CWF designation to HQ-CWF
- based on "Class A" Wild Trout Waters

The redesignation of the basin from Brizzee Hollow to Clara Creek to HQ-CWF affects 26.3 stream miles. This proposed designation would provide the same degree of protection to the candidate basin as the original request from the PFBC.