Chapter 8 – Aquatic Habitat 8.1 Existing Conditions ................................................................................................................................ 2 Importance of Aquatic Habitat ................................................................................................ 4 Riparian and Forest Ecosystems .............................................................................................. 5 Streams .................................................................................................................................... 9 Wetlands ................................................................................................................................ 16 Lakes .................................................................................................................................. 18 Puget Sound ........................................................................................................................... 19 8.2 Regulatory Requirements ................................................................................................................... 20 Clean Water Act ..................................................................................................................... 20 Endangered Species Act ......................................................................................................... 20 Salmon Recovery Act ............................................................................................................. 21 Shoreline Master Program ..................................................................................................... 21 Critical Areas Ordinance ........................................................................................................ 21 Drainage Design and Erosion Control Manual ....................................................................... 21 Low Impact Development ...................................................................................................... 21 Thurston County Noxious Weed Board ................................................................................. 21 8.3 Habitat Studies and Land Cover Analyses ........................................................................................... 22 City of Olympia Wildlife Habitat Study (1994) ....................................................................... 22 Aquatic Habitat Evaluation & Management Report (1999) .................................................. 22 GIS Basin Analysis (2012) ....................................................................................................... 22 City of Olympia Habitat and Stewardship Strategy (2013) .................................................... 23 West Bay Environmental Restoration Assessment (2016) .................................................... 23 8.4 Challenges ..................................................................................................................................... 23 Multiple Public/Private Ownership ....................................................................................... 23 Habitat Fragmentation .......................................................................................................... 23 Legacy Development and Land Development Pressure ........................................................ 24 Climate Change ...................................................................................................................... 24 DRAFT Storm and Surface Water Plan | Chapter 8 | Aquatic Habitat Maps Map 8.1 Aquatic Habitats in Olympia and Urban Growth Area .............................................................. 3 Map 8.2 Types of Aquatic and Terrestrial Habitat in Olympia and Its Urban Growth Area, 2013 .......... 6 Figures Figure 8.1 Habitat Loss in Olympia ............................................................................................................. 7 Figure 8.2 Olympia B-IBI Scores Compared to Thurston County and Puget Sound Averages. ................ 13 Figure 8.3 Relationship of Water Quality Index to Percentage of Basin without Treatment. ................. 15 Figure 8.4 Relationship of B-IBI Score to Percentage of Basin without Treatment ................................. 15 Tables Table 8.1 Typical Aquatic and Terrestrial Species in Olympia (*=nonnative) ........................................... 5 Table 8.2 Riparian Cover by Basin ............................................................................................................. 7 Table 8.3 Benthic Index of Biotic Integrity (B-IBI) Data for Olympia’s Streams ...................................... 12 Table 8.4 Basin Impervious Surface and Water Quality Parameters ...................................................... 14 Table 8.5 Fish Barriers in Olympia Watersheds ...................................................................................... 16 DRAFT City of Olympia Storm and Surface Water Plan August 2017 Chapter 8 – Aquatic Habitat Page 1 CHAPTER 8 – AQUATIC HABITAT The need to protect aquatic habitat from damage caused by stormwater runoff and other results of urban development is one of the major “Why’s” determining the strategies recommended for the Utility’s next ten years, as described in Chapter 10. In undeveloped areas, mature forests generate very little runoff directly to streams and other aquatic habitats. In urban areas, stormwater runoff generally travels from impervious surfaces (streets, sidewalks, roofs, and parking lots) to creeks and wetlands via pipes and ditches instead of slowly filtering into the ground. These increased flood flows carry pollutants directly into streams, wetlands, lakes, and Puget Sound (see Chapter 7). Chapter 4 describes how streams, wetlands, lakes, and marine waters function as “natural infrastructure” for stormwater management. This chapter focuses on how land development – increasing impervious surfaces, filling and altering wetlands, removing forests, and altering shorelines – has impacted the health and extent of aquatic habitat. In addition to identifying and evaluating aquatic habitat, the Utility’s role in habitat management includes education and outreach, stewardship planning, and restoration and enhancement projects. These activities are described in Chapter 9. 8.1 Existing Conditions The condition and extent of Olympia’s aquatic and associated habitats underlies the Utility’s focus on protecting, enhancing, and restoring habitat. A variety of aquatic habitats exist within Olympia, shown in Map 8.1, including streams, wetlands, lakes, and the marine waters of Budd Inlet: Eight named streams and smaller unnamed streams spanning almost 39 miles and with approximately 3,250 acres of riparian areas within 250 feet of a stream An estimated 680 acres of wetlands 16 freshwater lakes and ponds covering over 370 acres 10.4 miles of marine shoreline and over 750 acres of Budd Inlet (includes Urban Growth Area) Chapter 4 contains an inventory of these resources in Tables 4.1, 4.2, and 4.3. This section describes the aquatic habitat functions and species dependent on these habitats, and then reviews available data and specific functions of the various habitat types: riparian vegetation and upland forest, streams, wetlands, lakes, and Budd Inlet. DRAFT City of Olympia Storm and Surface Water Plan August 2017 Chapter 8 – Aquatic Habitat Page 2 Map 8.1 Aquatic Habitats in Olympia and Urban Growth Area DRAFT City of Olympia Storm and Surface Water Plan August 2017 Chapter 8 – Aquatic Habitat Page 3 Importance of Aquatic Habitat Aquatic habitat areas provide functions and benefits that are critical to maintaining water quality, natural hydrology, and habitat for fish and wildlife. These functions and some of the species dependent on these habitats are summarized below. Aquatic Habitat Functions Aquatic habitats in Olympia vary in habitat quality and function. Streams provide cool clean water for fish and other wildlife, wetlands and ponds accommodate breeding amphibians, riparian forests offer corridors for birds and other wildlife. They also manage stormwater by conveying water and sediment downstream, regulating flood flows, and filtering water to remove fine sediment, nutrients, and pollutants. Factors that influence these functions include past and present land uses, extent of impervious surfaces, effectiveness of stormwater management, connectivity between riparian vegetation and upland forests, vegetation species diversity, canopy layering and spatial diversity, and hydrologic alterations (e.g. culverts, fill, and ditches). An often-neglected factor is how conscientious neighboring residents are in maintaining buffers of native plants, managing vegetation on their property, properly using pesticides and other toxic substances, and maintaining drains and onsite sewage systems. Hydrologic changes due to development and increased impervious surface are often the largest stressor on aquatic systems. Urbanization impacts five critical stream attributes: flow regime, physical structure, water quality, energy sources, and biotic interactions (Booth (2001). Aquatic Dependent Species Migratory fish use stream and rivers for a portion of their life cycle coming into freshwater from the ocean to breed (e.g. salmon and lamprey). Resident fish spend all their lives in freshwater (e.g. trout and stickleback). Aquatic insects feed on microorganisms and provide source of food for many fish and wildlife. Freshwater mussels and crawfish