2.11      Watershed Problems and Opportunities

2.11.1	Overview
2.11.2	Data Needs
2.11.3	Assessment of Risks

2.11.1       Overview

A focus for watershed management efforts in urban areas is to protect the remaining high quality habitats first (e.g., opportunities), and than restore the rest in a prioritized approach (e.g., problems or challenges).  Opportunities are watershed conditions or features that are currently in a healthy, properly functioning condition and that are considered key to sustaining important watershed functions. Problems or challenges are watershed conditions or features that are not properly functioning or that contribute to impairment of watershed health. Furthermore, one method of analysis suggests that restoration of these conditions will result in significant benefits for indicator species that depend on those conditions (See ESA Framework for Watershed Health, pages 5-8, Portland BES 2002). Analyzing existing conditions and comparing them to reference conditions determine problems and opportunities. The following discussion highlights the analyses used to identify well-established problems and opportunities, what those problems and opportunities are, and where they are located in the watershed.

Fixing problems and restoring functioning conditions within the watershed will require an assessment of limiting factors. The assessment will focus on key processes that contribute to the limiting factors. Problems range from local to watershed-wide and solutions will vary in scale and in length of time necessary to achieve results. For example, much of Johnson Creek is devoid of large woody debris (LWD). LWD plays an important function in providing habitat and diversity to the channel, aids in pool formation, and provides structure for other aquatic insects. LWD can be placed and anchored into targeted site-specific locations where it is missing, but for long-term sustainability, wood recruitment is the key process involved in maintaining future wood deposition. Revegetation of the riparian corridor involves all of the upstream contributing watershed area, time to attain a suitable growth size, and time for trees to decay and eventually fall into the creek. This is a long-term restoration action given the growth rates of trees.

A list of the most outstanding data gaps is presented below first followed by a discussion that summarizes the areas of risk in terms of human activities, urbanization, and other foreseeable threats. An examination of significant results from an Ecosystem Diagnosis and Treatment (EDT) model output follows that will assist in focusing restoration actions and protection activities. Key functions and limiting factors are highlighted for each of five major sections of the watershed including: 1) Lower Johnson Creek; 2) Middle Johnson Creek; 3) Upper Johnson Creek; 4) Crystal Springs Creek; and 5) Kelley Creek. And finally, a summary of the highest priority areas and actions needed for protection, restoration, inventorying and monitoring, public policy and rules; and public involvement and education.

2.11.2       Data Needs

Although a wealth of information is available for many functional elements of the Johnson Creek watershed there are a few areas where data is missing or inadequate. These information gaps include:

1. Specific WPA locations and condition;
2. Toxics sampling and analysis (sediment and fish tissue);
3. Bacteria identification and tracing;
4. Fish usage areas and locations of refugia areas;
5. Outfall discharge characterization;
6. Upper watershed tributary instream habitat conditions;
7. Fish barriers on private lands;
8. Vegetation classes;
9. Pollutant sources and loadings;
10. Upland habitat and wildlife resources;
11. Crystal Springs Creek and Kelley Creek EDT ranking results of survival factors for successful coho salmon trajectories, capacity, and productivity;
12. Cutthroat trout EDT Model results; and
13. Water rights information.

2.11.3      Assessment of Risks

Watersheds face a multitude of risks. These include risks from human population growth and associated activities as well as natural and anthropogenic climatic changes. Risks from human activities generally include development practices, agricultural and industrial land practices, vegetation removal, and changes to the landscape including filling of wetlands, drainage course alterations, the addition of impervious surfaces and resultant increase in stormwater runoff, debris and refuse, and point and nonpoint pollution loadings. Natural and human-induced climate changes can alter watershed hydrology through increased flooding or droughts. 

Urbanization of watersheds continues to be one of the leading causes of degradation. Impacts to riparian areas and the increase of impervious surfaces including sidewalks, driveways, rooftops, and roadways contribute to significant hydrologic alterations.  Removal of vegetation can lead to increased runoff, sediment loading and sedimentation. As a result, stream hydrology can be altered for both high flows where flooding can become more frequent and severe and where baseflows can be reduced earlier and remain problematic longer during the dry season.

In addition, agricultural uses can significantly contribute to water quality problems. Removal of riparian vegetation, streambank erosion, and instream water diversions can result in excessive sedimentation and increases in water temperatures. Other foreseeable threats to watershed health in Johnson Creek include continued growth and development pressures and associated increases in stormwater runoff and potential for erosion with urbanizing areas including Pleasant Valley, Springwater, and Damascus. Climate changes as well as new nonnative invasive species may also pose a threat in the long-term. Other threats include inadequate or poorly enforced erosion prevention and sediment control policies and programs.

The City of Portland has identified linkages between indicators of human influences and their impacts on Riverine-Riparian indicators for use in measuring watershed health.  These indicators and linkages are summarized below in Table 14:

Table 14.  Linkages between the Indicators of Human Influences and Activities and their impacts on the Riverine-Riparian Indicators

Source: City of Portland Internal and IST Review Draft - A Summary of the Framework for Integrated Management of Watershed and River Health. 2002.