ODFW AQUATIC INVENTORIES PROJECT

STREAM REPORT

STREAM: Fanno Creek LLID: 1227639453931

BASIN: HUC NUMBER: 17090010

SURVEY DATE: September 5 - 12, 2019

ECOREGION: Willamette Valley Plains - Foothills STREAM ORDER: 3

USGS MAPS: Lake Oswego WATERSHED AREA: 8km2

FIRST ORDER : 5

SURVEY CREW: Erin Fulop and Courtney Jackson

REPORT PREPARED BY: Peggy Kavanagh

GENERAL DESCRIPTION:

The Fanno Creek stream habitat survey began at a property boundary and ended in the headwaters. Four reaches were designated based on geomorphology and junctions. There were 3,838 meters of primary channel length and 55 meters of side channel habitat. The land use was urban. Half of the surveyed channel contained scour pools with a smattering of riffles and beaver pools. Eighteen percent of the survey length was not surveyed due to access limitations caused by vegetation and lack of landowner support (denials or lack of response). Stream substrates were predominantly sand, gravel, and cobble. Non-native vegetation included English ivy, Himalayan blackberry, Travelor’s joy, Japanese knotweed, English holly, bamboo, and reed canary grass. The trees encountered most frequently during riparian transects were hardwoods 3-15cm dbh.

REACH 1: (T01S-R01E-S18S) – 1274 meters – The Fanno Creek stream habitat survey began at a property boundary and continued to a geomorphic change. There were 1,274 meters of primary channel habitat. The stream channel was constrained by alternating hillslopes and high terraces in a broad valley. The average valley width index was 12 (range: 4.0-20.0). The average gradient was 0.9 percent. The land use was urban. The streamside vegetation included deciduous trees 50-90cm dbh. The surveyed stream channel was primarily scour pools (35%) and riffles (11%); forty-two percent was unsurveyed. The substrate was a mix of gravel (26%), sand (14%), cobble (27%), and bedrock (20%). The average residual pool depth was 0.33 meters. Instream wood volume was 0.1m3/100m.

REACH 2: (T01S-R01E-S18S) – 453 meters – The second reach extended to Ivy Creek . There were 453 meters of primary channel length and 5 meters of side channel habitat. The stream channels were constrained by alternating hillslopes and high terraces in a broad valley. The average valley width index was 10.5 (range: 1.0-20.0). The land use was urban. The streamside vegetation included deciduous trees 30-50cm dbh. The average gradient was 0.5 percent. The stream channel was dominated by scour pools (80%), and the primary substrates were sand (29%), gravel (45%), and cobble (18%). Ten percent of the units had undercut banks. The average residual pool depth was 0.44 meters. Instream wood volume was 0.5m3/100m. Himalayan blackberry and English ivy were noted during the riparian transect. Total number of trees per 100m2: 1.0 conifers and 0.3 hardwoods (based on 1 riparian transect).

REACH 3: (T01S-R01E-S17S) – 1,339 meters – Reach 3 began at the Ivey Creek confluence and extended upstream to a geomorphic change. There were 1,339 meters of primary channel habitat and 50 meters of side channel habitat. The stream channel was constrained hillslopes in a narrow valley. The average valley width index (VWI) was 4.3 (range: 1.0-11.0). Typically, the average VWI for a narrow valley is ≤2.5. Due to averaging, the VWI was 4.3. The average gradient was 1.9 percent. The land use was urban. The streamside vegetation included deciduous trees 15-30cm dbh. Ten percent of the habitat units had undercut banks. The stream channel was mostly beaver (30%) and scour (36%) pools with gravel (35%) and sand (32%) substrate. The average residual pool depth was 0.52 meters. Instream wood volume was 0.2m3/100m. English ivy, English holly, and Himalayan blackberry were encountered during the riparian transects. Hardwoods 50-90cm dbh were the tree most frequently encountered. Total number of trees per 100m2: 0.8 conifers and 1.7 hardwoods (based on 2 riparian transects).

REACH 4: (T01S-R01E-S17S) – 773 meters – The final reach encompassed a broad valley and ended at a property boundary. There were 773 meters of primary channel length. The stream channels were constrained by alternating hillslopes and high terraces in a broad valley. The average valley width index was 8.8 (range: 1.0-20.0). The land use was urban. The streamside vegetation included shrubs and deciduous trees 30-50cm dbh. The average gradient was 2.1 percent. Fifty-nine percent of Reach 4 was not surveyed due to abundant vegetation hindering access. That which was surveyed was a mix of riffles (11%), cascades (9%), and culverts (8%). The primary substrates were sand (39%) and gravel (37%). The average residual pool depth was 0.21 meters. Himalayan blackberry, English ivy, and English holly were noted during the riparian transects. The trees encountered most frequently in the were hardwoods 3-15cm dbh. The total number of trees per 100m2: 0.5 conifers and 1.8 hardwoods (based on 2 riparian transects).

COMMENTS:

Fish were not observed during the survey. A fish presence / absence survey was not conducted. Potential barriers to fish movement include a log step 1.2m high (unit 142, 2604m) and an old beaver dam 1.8m high (unit 160, 2839m).

Beaver activity was prominent in Reach 3 and consisted of pools, dams, and chewed sticks.

Columbia Creek and Lowell Creek entered inaccessible areas of the Fanno Creek survey in the vicinity of units 4 and 27, respectively. Restoration Creek entered Reach 3.

Hardpan clay was present during the survey. In the analysis, hardpan clay is represented as bedrock. Refer to the Comment Summary for individual units with hardpan clay substrate.

The upstream UTM coordinates for each stream habitat unit were recorded and listed in the Comment Summary. Due to capture error, unique coordinates were not collected for all units.

Invasive species noted during the survey were English ivy, Japanese knotweed, Himalayan blackberry, Travelor’s joy, English holly, and reed canary grass.

Select non-native plants in the Comment Summary were listed in order of presence within each habitat unit, and in some cases, the side of the stream where encountered. Ex. Veg=/EI, HBB/ indicates that English ivy was on the right bank and Himalayan blackberry was on the left bank. The “/” indicates the side of the stream, where ‘xx/’ = left bank and ‘/xx’ = right bank. Ex. Veg=EI/EI, HBB/, English ivy was on both sides of the stream and in greater presence than the blackberry which was on the left bank. Ex. Veg=EI, HBB indicates that there was more English Ivy than Himalayan blackberry and both were present on both sides of the stream. The lack of ‘/’ signifies that the vegetation was not bank-side-specific. Fanno Creek (Tualatin River Basin) 2019 Summer Habitat Survey Photographs

Reach 1 - Unit 5 - Looking downstream near the start of the new survey. Reach 1 - Unit 24 - The left riparian zone was smothered in ivy and blackberry.

Reach 1 - Unit 24 - Looking upstream at the habitat and streamside vegetation. Reach 1 - Unit 24 - The right riparian zone.

Reach 2 - Unit 29 - An upstream view. The streamside vegetation included Reach 2 - Unit 57 - An upstream view of the reach. jewelweed, bamboo, ivy, blackberry, and reed canary grass. Fanno Creek (Tualatin River Basin) 2019 Summer Habitat Survey Photographs

Reach 2 - Unit 57 - An upstream view. Reach 3 - Unit 98 - September rain rapidly increased the water level and flooded this pool habitat. The creek was blown-out for a day until waterlevels receeded.

Reach 3 - Unit 81 - Culvert crossing 1.6m diam, corrugated steel. Reach 3 - Unit 86 - A downstream view of the substrate and vegetation.

Reach 3 - Unit 86 - Looking upstream at the stream channel. Reach 3 - Unit 113 - Another view of Reach 3. Fanno Creek (Tualatin River Basin) 2019 Summer Habitat Survey Photographs

Reach 3 - Unit 158 - A beaver dam 0.5m high and the resulting beaver pond. Reach 3 - Unit 160 - Another series of beaver dams and pools. This beaver dam was 1.8m high and stable.

Reach 3 - Units 166 and 167 - Two culverts 0.8m diam round concrete set in creek Reach 3 - Unit 168 - The downstream view captured a stone wall 2m high. Crew running under Highway 10. The culverts start individually and end as a single culvert notes indicate this part of the creek is essentially a drainage ditch. 1.5m diameter. Unsure of split location.

Reach 4 - Unit 168 - An upstream view of the stream channel, complete with Reach 4 - Unit 180 - An upstream view of the new reach. ivy, holly, and blackberry. Fanno Creek (Tualatin River Basin) 2019 Summer Habitat Survey Photographs

Reach 4 - Unit 186 - Looking at the step-culvert sequence. The culvert was Reach 4 - Unit 187 - Looking back downstream at the upper end of the U187 culvert and 0.9m diam, corrugated steel, and ran under a footpath. substrate.

Reach 4 - Unit 188 - The left (left photo) and rigth (right photo) riparian zones at the survey end. The riparian included ivy and holly. The survey ended at a property boundary.

Overview of Fanno Creek.