Phase I Reconnaissance Report on Little Anderson Creek Habitat Restoration Assessment

Transcription

1 Insert photo here Phase I Reconnaissance Report on Little Anderson Creek Habitat Restoration Assessment Technical Memorandum Prepared for Hood Canal Salmon Enhancement Group P.O. Box 2169 Belfair, WA Prepared by Stillwater Sciences 1314 NE 43 rd Street, Suite 210 Seattle, WA, March 21, 2008

2 1 INTRODUCTION This memo constitutes Stillwater Sciences Phase I report to the Hood Canal Salmon Enhancement Group, as specified in the scope of work. The tasks associated with this phase of the project include providing the following: 1) a brief synopsis of a site visit to Little Anderson Creek on 13 th February 2008, 2) a brief review of available data and reports, 3) compilation of GIS data and development of base maps, 4) recommend elements of the Phase II follow-up office and field work in support of the proposed LWD enhancement project. 2 SITE DESCRIPTION The Site Description is based material from the Hood Canal Complex IMW Study Plan (2007). Little Anderson Creek is an independent east-side tributary to Hood Canal located south of Big Beef Creek. The Little Anderson Creek watershed is approximately 13-km2 and the smallest of the Hood Canal basin that are part of the network of Intensively Monitoring Watersheds. As such, it is included as one of the treatment basin in which habitat restoration actions will be evaluated in terms of their cumulative contribution to increased salmon production. The stream is bordered on the east by the City of Silverdale and a part of the watershed is within the urban growth boundary of the city. Little Anderson Creek is used by coho and chum salmon, and cutthroat trout. A few steelhead also spawn in the stream each year. Hypothesized constraints to coho production include: Preferred habitat is limited to the lowest 2.0-km of the mainstem, as high gradient tributaries within the watershed contribute little or no summer flow and thus provide little habitat; Habitat complexity is limited because the main channel lacks LWD to control bed movement and create juvenile salmon rearing habitat; Steep hillslopes, high channel gradients, and altered hydrology may degrade stream channels via various mechanisms, upstream of river kilometer (RK) 2.0 Sediment fluxes associated with high winter flows may precipitate scour and/or bury salmon redds below this point; Fisheries harvest may exert a higher-than-sustainable impact on Little Anderson Creek coho given its current low adult return and consequent limited productivity. Channel Form Most of Little Anderson Creek and its tributaries exhibit a channel form that is incised or cut into its floodplain. Stream gradient within the fish-bearing portions of Little Anderson Creek averages 3.1% (WDFW unpublished data). Most suitable habitat is found in the lower 2.0 km of the mainstem, where channel gradient is less than 2%. Upstream of this point, flow is evenly divided between the main channel and the right-bank tributary and the channel steepens to 3-5%. The combination of increased channel gradient and decreased summer flow likely limits the use of the stream above this point by anadromous fishes. Sediment Characteristics Although stream banks are largely intact within the Little Anderson Creek watershed, averaging less than 0.3-m 2 of exposed bank per meter of stream length, bed scour associated with high winter flow events has resulted in the transport of large amounts of sediment downstream. Large 1

3 quantities of sediment were deposited in the lower reaches of Little Anderson Creek following a 1994 storm when a road fill with an undersized culvert on Anderson Hill Road failed. This incident released large amounts of sediment accumulated above the culvert and resulted in a braided channel below the culvert. Although the culvert was removed and a bridge was installed in its place in 2002, damage to the channel as a result of the 1994 storm were still evident in Low to moderate levels of LWD were available to retain gravel and create pools resulting in little spawning and rearing habitat (WDFW unpublished data). Recently, beavers have constructed several dams in this reach and the channel has shifted widely across the valley floor in response the dams and high flows. 3 PURPOSE Phase 1 of this study consisted of four tasks: Initial site visit (Task 1); assembling and assessment of existing info (Task 2); identification of gaps, creation of base maps and GIS files and LiDAR evaluation (Task 3); define gaps, components of necessary field work and additional LiDAR /GIS development, and prepare a short memo-report detailing findings and defining a proposed field study plan (Task 4). 3.1 Site Visit On February 13th, 2008 Stillwater Sciences staff (Byron Amerson, Derek Booth, and Stephen Ralph) made a reconnaissance-level site visit with Richard Brocksmith (Hood Canal Coordinating Council) and Neil Werner of the Hood Canal Salmon Enhancement Group. We entered the creek downstream of where it is crossed by Northwest Newberry Hill Road, and traversed downstream for about 2.5 km. The purpose of the visit was to get a first-hand sense of the proposed site for the LWD installation project. Two general impressions from this field visit are that Little Anderson Creek is conveying abundant bedload, the source of which are its banks and bed; and there is an abundance of LWD in or near the channel, but the caliber of the LWD is small to medium and has relatively low habitat-forming function. The main source of sediment loading in the Little Anderson Creek appears to be erosion of the banks and bed of the creek itself, rather than external sources such as landsliding. There are some landslides that do contribute sediment to the creek, but the total volume of these slides is relatively small, so they probably contribute little to the bedload. However, landslides are likely the dominant source of sand and silt-sized particles to the creek. There are two relatively large tributaries to Little Anderson Creek in the reach that we traversed, each of which contributes a large and obvious sediment load to the mainstem channel. Below each tributary confluence there are impressive deposits of aggraded bedload. It is probable that much of the bedload aggraded downstream of the tributary junctions is material that was transported from the tributary streams during the flooding from the December 2007 rainstorm of record. For some distance downstream of each confluence the channel is well-connected to its floodplain. Here, the channel meanders and exhibits an alternating sequence of shallow pools and riffles with well developed gravel bars. As the ratio of bedload to discharge attenuates in the depositional reaches below the tributaries, the channel takes on an incised form that disconnects it from the adjacent floodplain. Thus, there are repeated sequences of deposition and scour through the stream, each with distinct channel morphology (Figure 1 and Figure 2). 2

4 Figure 1. Aggraded channel in Little Anderson Creek. 3

5 Figure 2. Incised portion of Little Anderson Creek. Note elevation of adjacent floodplain. Deposits of LWD in Little Anderson Creek are relatively abundant. There are both single pieces of wood and accumulations of wood; in either case some wood is spanning the channel, and some fewer pieces are partly or completely in the channel where it can contribute to habitat complexity. While no formal survey of the wood was done, the impression was that most of the wood is of small to medium diameter (< 30 cm). Larger diameter pieces are invariably relict pieces of Western Red Cedar and were usually less than about 3 m long. Most of the wood that is interacting with the bed appears to be largely buried by bedload. Very few pieces have created localized scour and deposition creating habitat heterogeneity, but rather back up an impoundment of gravel or simply occur as individual pieces evenly embedded in the substrate. There were several impressive introductions of newly fallen wood evidently from the December 2007 flooding, including several toppled clusters of trees that cause localized channel planform change. There are woody debris jams that accumulate deposits of sediment behind them, several of which force the channel to erode through the nearby areas of the floodplain. 4

6 Figure 3. Embedded LWD in Little Anderson Creek. Pool habitats in particular appear to be poorly represented within the channel. While there are a fair number of locations exhibiting this channel planform change and reorganization, overall the channel heterogeneity appears minimal, especially with regard to variation in depth. Very few scour pools associated with LWD were observed. Overall, the general impression we came away with is that that there is a lot of LWD, but that it was small diameter, was inundated by bedload, and contributes little to habitat complexity. 3.2 Analysis of available Data and identification of gaps A variety of spatial data and recent fisheries science reports were assessed for their utility in informing the proposed LWD enhancement project Spatial Data To ensure that we take advantage of existing spatial data in our characterization of the basin, we have accumulated information from contacts with State and County agencies. Spatially explicit data is abundant for the Study Area, and is available from Washington Department of Natural Resources (WDNR), the Washington Department of Ecology (WDOE), the Washington Department of Fish and Wildlife (WDFW), the Washington State Department of Transportation (WDOT), Kitsap County, the University of Washington, and the Puget Sound LiDAR Consortium. Spatial data is stored in repositories that are easily accessed via the web. A summary of available spatial data and sources is presented in Table 1. Generally speaking, the 5

7 spatial data that is available provides supporting background information that will be useful to subsequent basin analysis and recommendations for habitat restoration through placement of LWD in Little Anderson Creek LiDAR Data High-resolution digital topography based on LiDAR surveys is useful in a variety of ways. Shaded relief maps based on LiDAR help to visualize relatively fine scale features of the landscape that may be of interest in a given analysis. More importantly quantitative analyses of topography can be made using LiDAR data. Landscape qualities such as slope are wellrepresented based on LiDAR data. The course of stream channels, channel slope, and variety of other channel characteristics can be calculated based on LiDAR. The caveat is that the channel attributes so calculated are only as good as the calculated stream courses they are based upon, which can be problematic with high-resolution topographic data in low gradient areas. The flowaccumulation algorithms employed by GIS have difficulty with routing flow through sinks depressions in the data, road and bridge crossings, and ditches. Puget Lowland topography in particular presents special challenges, because of low-gradient headwaters and prevalent wetlands throughout typically small basins. An example of a possible artifact in stream channel calculation is apparent in the hydrology layer based on LiDAR supplied by Kitsap County for Little Anderson Creek. In the lower 2 km there appear to be several reaches of the stream that are multi-threaded (Figure 4). While this may be true, it is not clear whether field evaluation has confirmed that the channel is multi-threaded. Ned Pittman (personal communication, February 12, 2008) mentioned that some of the Hood Canal IMW streams had been walked with GPS to locate the stream channel, but he did not mention Little Anderson Creek. For example, confidence that the stream network as calculated by the GIS is accurate is an important component of quality control for data that may be used in subsequent algorithms that predict channel slope or particle size distribution. 6

8 Figure 4. Map of Little Anderson Creek basin. 7

9 Geology Mapping The geology and soils mapping information that is available is too coarse and preliminary to be of use for this work WDFW EMAP Data Physical attribute measurements of IMW streams are being collected by the WDFW field staff, using the EPA s environmental monitoring and assessment protocol (EMAP). Channel dimensions, wood loading and several other channel attributes have been collected to date and more are planned. The channel attributes and EMAP methods are described in more detail in the IMW Hood Canal Complex Study Plan. The spatial location of each EMAP site is collected and stored in a spatially referenced database which can be plotted (Figure 1). There are several EMAP sites located in Little Anderson Creek within the area of proposed LWD enhancement. The WDFW EMAP is the single best dataset of physical and habitat attributes for Little Anderson Creek. There are many EMAP sites throughout the basin, and the data is collected based upon an established and reasonably repeatable protocol. The WDFW EMAP database is still under construction, and so data summaries are not available (Kirk Krueger, personal communication March 13, 2008). However data for specific channel attributes are available in their raw form. We requested data, collected from 2003 to 2007, on bankfull width, total reach length, and LWD tallies for each of the EMAP sites in Little Anderson Creek. From these data we were able to calculate wood loading for Little Anderson Creek for comparison with LWD loading data for Washington State (Fox 2001). Understanding the relative amount of wood presently found within the channel and its floodplain is important to defining the best locations for any additional wood placement. Based on the WDFW EMAP data, wood loading in Little Anderson Creek falls within the bounds of wood loading in undisturbed basins from around Washington State (Figure 2). This finding is in contrast to the determination in Hood Canal Complex IMW Study Plan (2007) which states that Main channel lacks LWD to control bed movement and create rearing habitat. However, in Little Anderson Creek, our general impression is that LWD has relatively small diameter and has low habitat function, despite relatively high abundance. 8

10 LWD Volume per Channel Width LWD Volume/CW in WA Rivers Little Anderson Total LWD Bankfull Width (m) Figure 5. Wood loading in Little Anderson Creek in comparison to undisturbed Washington State rivers (plot based on data from Fox 2001 and WDFW EMAP in Hood Canal IMW creeks) Basin Hydrology Hydrologic data for Little Anderson Creek is scant. There is a stream gage on the creek that is maintained by WDOE which has been active since late The stream gage data can be accessed via the following URL: A much longer hydrologic record is available for a nearby regional stream, Big Beef Creek, from a stream gage maintained by the USGS (gage ). Historically, the characteristic discharge Puget Lowland was supplied primarily by slow metering of water from headwater wetlands and groundwater. These headwater wetlands, primarily developed over the upland surface of glacial till that mantles much of the Puget Lowland region, and a dense cover of ancient tress absorbed most runoff from even very large storm events, allowing it to be absorbed and infiltrated to groundwater. The modern hydrologic function of these systems has been altered by drainage of wetland systems, removal of a once-dense forest cover, and development of runoff-conveying road networks. These alterations result in more rapid runoff and higher flood peaks, although this reconnaissance was too brief to quantify these changes. More rapid runoff generally reduces groundwater recharge, and so the annual water supply enters the stream more quickly than in the past. The higher flood peaks have a higher transport capacity and a greater fraction of coarse sediment transported is locally derived by erosion of sediment stored in valley-bottom deposits. We were not able to discern the extent to which this basin is beginning to exhibit the influences typically seen with urbanizing basins in Puget Sound. 9

11 Sediment Supply There are no data or studies that specifically explore sediment supply sources or sediment transport dynamics in Little Anderson Creek. There has been limited research on hydraulic geometry relationships and sediment transport in nearby Puget Lowland streams, and while relevant, the research is dated (Madej, 1978). Our observations in Little Anderson Creek and Seabeck Creek suggest that there are few point sources of course sediment in the creeks. There is some landsliding, but not enough volume is introduced in any one slide to account for the large accumulations of sediment present in the basin. However, landsliding in glacial outwash deposits is likely to be the main source of sandy and silty sediment in the creeks. Our working hypothesis is that most of the modern sediment supply in Puget Lowland streams comes from incision of valley bottom deposits and pervasive bank and bed erosion of the creeks themselves. This general conclusion was presented in the Hood Canal Complex IMW Study Plan (2007) as well. See our Seabeck Creek Technical Memorandum (2008) for further discussion of the processes involved Published Reports The most recent and comprehensive discussion of relevant fisheries and stream habitat issues is the Hood Canal Complex IMW Study Plan (2007). This report sums up historical and recent research and presents a comprehensive summary of the physical and ecological attributes of the four Hood Canal IMW streams, including Little Anderson Creek. There are several WDFW reports concerning juvenile and adult salmonid sampling efforts over the last few years which can be found on the web at: These reports provide basic descriptive and supporting information, but do not provide specific analyses of LWD and fish habitat that would support the present work. 3.3 Recommended Next Steps Based upon the site visit and analysis of existing information, we recommend that the following additional field work be done in Phase II of the project: A. A more comprehensive survey of sediment sources in mainstem Little Anderson Creek and the two main tributaries in the proposed enhancement reach. This is necessary because it provides a relative indication of sources and volumes of sediment entering the channel in recent decades. a. To determine if there the source of sediment in the creek (i.e. point or non-point source) b. To determine if sediment loading to the mainstem is episodic or chronic c. To determine is future investments in wood addition to the channel are wise in light of the long-term effects of mobile sediment fluxes coursing through the channel. d. To help refine the suite of recommendation for habitat enhancement and better understand the relative merits of each in terms of increasing salmon productivity. These recommendations might include actions in addition to wood placement. e. Get more insights into the influence of basin hydrology on sediment flux 10

12 B. Site visit to determine the sub-reaches of the channel network best suited for LWD enhancement a. Define those sub-reaches most likely to retain placed LWD A Final Caveat The habitat and ecological outcomes of placement of LWD in Little Anderson Creek and other Puget Lowland streams are not well-known. Ostensibly, placing LWD in channels is done to improve habitat for, and in turn increase populations of salmon and trout. Understanding the physical process context, particularly in light of incipient urbanization, is paramount to informed habitat improvement actions. Understanding changes in hydrology, sediment supply, and sediment transport dynamics are of particular importance. For example, our observations in Little Anderson Creek suggest that the sediment supply could simply bury LWD installations. If that were to happen, sediment may be effectively retained in the stream channel, but habitat value may be minimal. Alternatively, the flood of 2007 demonstrated that Little Anderson Creek has the capacity to mobilize and transport LWD that has been placed for habitat improvement. Our additional field work may allow us to better characterize these issues as it relates to the spatial and temporal characteristics of habitat forming processes in this stream channel. Hypothesis-driven planning and monitoring is a useful approach for a project such as this. As the LWD placement project moves forward, keeping the driving hypotheses in mind is worthwhile to help guide decision-making a priori, and to keep goals in mind as part of the post-project monitoring process. Governing Hypotheses from the Hood Canal Complex IMW Study Plan (2007): H1: The increase in outmigrant production following habitat restoration is greater in treatment watersheds than in reference watersheds. H2: The increase in mean parr population, growth, and density is greater in treated watersheds than in control watersheds. H3: The increase in mean egg to parr survival is greater in treated watersheds than in control watersheds. H4: The increase in mean parr to smolt survival is greater in treated watersheds than in control watersheds. H5: Restoration results in a measurable increase in habitat, basin wide. H6: The geographic distribution of spawners is correlated with maximum November flow, with escapement, and with smolt production. H7: Summer low flows are correlated with habitat quantity and quality and with parr-smolt survival. Example LWD Enhancement Hypotheses: H1: Treatment will increase both localized sediment deposition and scour. H2: Treatment will decrease channel widths per pool. H3: Post-treatment pools will be deeper than pre-treatment pools. 11

13 H4: Post-treatment pool area per channel width will increase. H5: Pools created by wood jams will be used by juvenile salmonids References Fox, M. J A new look at the quantities and volumes of wood in forested basins of Washington State. Master s thesis. University of Washington, Seattle. Ehinger, W., T. Quinn, G. Volkhardt, M. McHenry, E. Beamer, P. Roni, C. Greene, R. Bilby Hood Canal Complex IMW Study Plan. Madej, M MS Thesis, College of Geology, University of Washington (citation pending) Table 1. Available spatial data and source for Little Anderson Creek. Watershed Coverage Type of Information Form of Information Information Contents Source Contains road line segments; road name; road type (street, highway, bridge, etc.); road functional identification (e.g., rural, interstate) Land Use GIS shp Majority of WS Stream Networks EMAP Data Collection Locations Building Footprints Big Beef Creek, Little Anderson Creek, Seabeck Creek, and Stavis Creek basins Big Beef Creek, Little Anderson Creek, Seabeck Creek, and Stavis Creek basins Clipped LiDAR Layer GIS shp based on 2000 LiDAR data GIS shp based on 2007 surveys GIS shp GIS shp Excel spreadsheet GIS DEM 1:12,000 LiDAR DEM map GIS DEM 1:12,000 LiDAR 5-foot Contours Maps GIS shp Contains stream networks for Little Anderson Creek, Seabeck, Big Beef Creek, and Stavis Creek watersheds; Stream segment length; Cumulative contributing stream segments length per segment; Strahler system ID per segment Contains data collection points Contains polygon data for building footprints location, orientation, and area; Data based on 2005 WA DNR and 2001 Space Imaging compiled by Kitsap County GIS and on 1998 Walker compiled by Walker and Associates Contains polygon area for each of the four watersheds Contains perimeter length and area in square mileage and acreage for each of the four watersheds Clipped LiDAR layer LiDAR Topographic Map; 2000 flight date; few areas reflown in 2002; 1:12,000 (1 inch=1,000 feet) scale; vertical datum is NAVD88. LiDAR 5-foot Contour Maps by Section WADFW via Kitsap Co. via WADFW corrected using LiDAR and field survey GPS data via WADFW, these are sample data collected using a modification of the USEPA EMAP methods WADFW via Kitsap Co. WADFW WADFW WADFW via LiDAR Consortium WADFW via LiDAR Consortium Kitsap Co GIS Website 12

14 DAIS 2001 Imagery (Air Photo) DAIS 2001 Imagery (Air Photo) Kitsap County and surrounding areas Hill shade of Kitsap County Environmental Features Layers Geology Layers GIS raster dataset (MrSID) GIS raster dataset (MrSID) GIS tile GIS tile GIS shp GIS tiles and shp (ESRI_shp) Soil Layer GIS shp (ESRI_e00) Climatology: Rain on Snow GIS shp (ESRI_e00) Elevation GIS shp (ESRI_grid) Elevation GIS shp (ESRI_grid) 2001 Digital Airborne Imagery System (DAIS) of Kitsap County by Section 2002 Digital Airborne Imagery System (DAIS) of Kitsap County (entire) 10m grids of Kitsap County derived from USGS DEMs; 3-band, 3-meter per pixel imagery of Kitsap County. 10m grids of Kitsap County derived from USGS DEMs Includes geological hazard areas, overlay of soil type & suitability, sixth field (HUC 6) watersheds, soil stability from Deeter soil survey, surface geology, wetland mosaic Digital 1:100,000-scale Geology of Washington State; includes layers: Quadrangle, county, state boundaries; attitude measurements; age date sample locations; individual igneous dikes; fold axes; linear geologic features; point geologic features; dike swarm boundaries; dike swarm polygons; contacts and faults; geologic unit polygons; volcanic vents and eruptive centers Kitsap County soils - July 2003, State soils mapping program Statewide coverage, November 1991 data 30m DEM; DEM30 is a statewide (and beyond) ARC/INFO GRID (raster) coverage depicting surface elevation. It was derived by resampling USGS 10-meter DEMS (Digital Elevation Models). All source data was scanned from the hypsography (contour) separate used in the publication of USGS 7.5 minute quadrangles, and is classified as LEVEL 2 DEM. 90m DEM; DEM90 is a statewide (and beyond) ARC/INFO GRID (raster) coverage depicting surface elevation. It was derived by resampling the DEM10 data layers. The DEM10 data layers were derived from USGS 10-meter DEMS (Digital Elevation Models). All source data was scanned from the hypsography ( tsap.wa.us/sectiondo wnloads.htm) Kitsap Co GIS Website ( tsap.wa.us/sectiondo wnloads.htm) Kitsap Co GIS Website ( com/gis/metadata/) Kitsap Co GIS Website ( com/gis/metadata/) Kitsap Co GIS Website ( com/gis/metadata/) Kitsap Co GIS Website ( com/gis/metadata/) 13

15 Forest Practices: Sitka Spruce Zone Forest Practices:Landsli de Hazards Forest Practices:Slope Stability Hydrography for Kitsap County Wildfire statistics and risk assessment GIS shp (ESRI_e00) GIS shp (ESRI_e00) GIS shp (ESRI_e00) GIS shp (ESRI_e00) GIS shp (ESRI_shp) 10m DEM GIS shp (.dem) (contour) separate used in the publication of USGS 7.5 minute quadrangles, and is classified as LEVEL 2 DEM. Statewide coverage of Landslide Hazard Zone Compilation Status, January 2008 Statewide coverage of Modeled Slope Stability; This coverage is a predictive data layer of shallow-rapid slope stability using one or more calibrated GIS-based models. This grid covers all forested watersheds of western Washington State. This data layer is an anticipated outcome of the Forestry Module negotiations as outlined in the Forest and Fish Report (1999) and legislated in the Engrossed Substitute House Bill 2091 (1999). WCHYDRO and WBHYDRO together make up the most complete and up to date hydrography layer for the State of Washington. WCHYDRO contains watercourses represented as arcs or lines. These occur alone as single arc watercourses representing streams, ditches, or pipelines, or as centerlines through water body polygons such as doublebanked streams, lakes, impoundments, reservoirs, wet areas, or glaciers. WBWS (WBHYDRO) and WC (WCHYDRO) are edited daily and simultaneously; updates are posted weekly for internal DNR use and monthly for external use. Attribute interrelationships within WBWS (WBHYDRO) and spatial and attribute interrelationships between WBWS (WBHYDRO) and WC (WCHYDRO) are maintained. This dataset includes information about wildfires that have occurred on lands protected by the Washington State Department of Natural Resources.; This theme is based on data from the current National Fire Protection Association (NFPA 299) risk assessment, and includes one or several communities with similar wildfire risks. 10-meter DEM files for Seabeck and Wildcat Quads UW Geomorphological Research Group ( ngton.edu/data/raster/ tenmeter/byquad/seat 14

16 Mouth of Creek 2005 DEM combined bathymetry and topography for Puget Lowland 2005 LiDAR 6- foot grids Oblique aerial images GIS DEM (raster; ESRI ASCII grid format) GIS (ESRI_e00).jpg 2005 combined bathymetry and topography of the Puget Lowland; incorporates LiDAR topography and swath bathymetry); raster 2005 Bare Earth LiDAR DEM 1992 Shoreline aerial photos along entire Puget Sound (including Hood Canal) shoreline tle/index.html) UW Geomorphological Research Group ( shington.edu/data/pug etsound/psdem2005.h tml) UW Geomorphological Research Group ( r.ess.washington.edu/ lidardata/restricted/) WA Department of Ecology ( v/shorephotos/index.h tml) 15