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| 2.5.1 | Land Use |
| 2.5.2 | Current Development |
| 2.5.3 | Future Development |
| 2.5.4 | Impervious Surfaces |
| 2.5.5 | Roads |
| 2.5.6 | Channelization |
| 2.5.7 | Water Rights |
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The land use varies from heavily developed urban areas in the lower and middle reaches of the Johnson Creek watershed (Cities of Portland, Milwaukie, and Gresham) to rural and agricultural in the upper watershed (Figure 2 (PDF, 260KB). Current land use (1999) in the basin reveals single-family residential and rural designations make up the largest acreage and percentages at approximately 15,000 acres or 45 percent and 11,000 acres or 33 percent respectively (Meross, 2000). Multi-family residential accounts for 9 percent, while industrial and commercial taken together make up 8 percent. Parks and open space account for the remaining 5 percent. In the agricultural rural areas of the upper watershed, 50 percent of the land base is currently used for cultivated crops or pastures, and another 29 percent is used for tree and ornamental nurseries, greenhouses, or Christmas tree plantations (Meross, 2000). There are currently 49 developed parks and recreational facilities within the Johnson Creek Watershed, totaling more than 1,000 acres (City of Portland BES, 2000). The Springwater Corridor Trail is a key recreational facility in the watershed. It extends more than 16 miles and occupies a former railroad right-of-way paralleling Johnson Creek for much of its length.
The Johnson Creek Watershed is highly developed with over 50 percent of the watershed urbanized. Development consists primarily of buildings and structures, stormwater and sanitary systems, roadways, bridges, pipes, outfalls, and culverts. Metro estimated that approximately 38 percent of the tributaries were piped or relocated by development over the years (Meross, 2000). These drainage systems originated mainly in the northern portion of the watershed within Portland and a portion of Gresham. However, as noted earlier, the east side terraces do not have a well-developed stream in all areas and precipitation that falls on mostly permeable sand and gravel percolates to groundwater and leaves the area by underflow (Laenen, 1980).
The urban growth boundary (UGB) for the Portland metropolitan region passes through the Johnson Creek watershed. In 1997, Metro approved a UGB expansion including the 1500 acre area known as Pleasant Valley, which roughly corresponds to the Kelley Creek watershed. With this expansion, about 72 percent of the watershed’s 34,000 total acres, or approximately 24,000 acres of the watershed, lie within (Meross, 2000). In 2002, as the Pleasant Valley Concept planning process drew to a close, the Metro regional government expanded the urban growth boundary again. The bulk of the 2002 expansion area consists of more than 13,000 acres south and east of Gresham, including approximately 3000 acres of the Johnson Creek Watershed. The UGB and Expansion Areas are shown on Figure 3 (PDF, 487 KB).
Much of the existing development consists of impervious surfaces. Impervious surfaces as a percentage in the Johnson Creek watershed were estimated from aerial photographs and zoning maps. Within Portland, approximately 29 percent of the watershed is covered with impervious surfaces. Approximately 43 percent of the watershed as a whole is covered with impervious surfaces. This percentage was derived from BES’s multispectral vegetation data analysis (Young, BES, 2003). The amount of impervious area increases as you go downstream in the watershed from the agricultural areas of the headwaters to the inner city at the mouth with as much as 45 percent impervious area within the Crystal Springs Creek sub-watershed. It is important to note that a large percentage (35 percent) of the lower watershed does not drain to Johnson Creek as overland flow. Approximately 23 percent of the watershed in the Portland region of the watershed drains to groundwater through stormwater sumps. Approximately 8% is directed to Portland’s combined sewer system, and approximately 6% is hydrologically disconnected from the watershed (Meross, 2000). Percent effective impervious within the Johnson Creek watershed varies considerably; large areas in the middle and upper watershed areas have relatively low effective imperviousness that swamps out high percentages in the lower watershed. The net result is that overall, very little of the watershed actually exceeds the threshold of 10-15% effective impervious (ESA, 2001).
Drainage patterns in the lower portion or western end of the watershed were significantly altered by construction of a piped storm drainage system (Johnson Creek Corridor Committee, JCCC, 1995). Within this area the Sellwood, Eastmoreland, Westmoreland, and Woodstock neighborhoods of Portland contain 110,832 lineal feet of the city’s combined sewer system within two basins- Lents 1 and Lents 2. There are no significant hydraulic problems in the Lents 1 basin; however, there are potential areas of basement flooding from saturated ground conditions and peak storm flows. Lents 2 has significant capacity problems that result in basement flooding. Problems are caused by undersized conveyances, flat slopes, and very long collection networks (Portland ESA, 2000). The Portland Public Facilities Plan (Portland BES, 1999) identifies capital improvement program (CIP) projects for both of these basins to address basement flooding and combined sewer overflow (CSO) reduction.
Stormwater within the city of Portland is conveyed through approximately 38,832 lineal feet of storm drainage pipe and is treated by 31 pollution reduction facilities within the watershed. It is then discharged into one of three main locations: the combined system, sumps, or directly into Johnson Creek. The sump or dry well area within the city limits in the portion of the watershed covers more than 8,000 acres and treats approximately 23 percent of the city’s stormwater.
Within Gresham’s portion of the Johnson Creek Watershed, stormwater is conveyed through 384,282 feet of stormwater pipe. As the soil north of Johnson Creek is appropriate for infiltration facilities, 47 sumps have been installed within the northern portion of the watershed, receiving runoff from a mix of commercial, residential, and transportation land uses. There are no combined sewer system pipes within Gresham’s city limits.
The public stormwater system within the upper portion of the watershed that extends from the 2002 Gresham UGB east approximately four miles to the watershed boundary consists of roadside ditches and culverts that convey runoff directly to Johnson Creek and its tributaries. In addition to surface water runoff, the ditch system carries water from farm field subsurface drainage systems to area creeks. The ditch system provides no water quality treatment other than in areas where ditch vegetation is maintained. For new developments, the rate of stormwater runoff from private property is required to be controlled to the pre-development amount under Multnomah County ordinances. Runoff from agricultural fields into the roadside ditch system is in the jurisdiction of the Oregon Department of Agriculture.
The Oregon Department of Environmental Quality (DEQ) through the federal National Pollution Discharge Elimination System (NPDES) Permit Program regulates stormwater. As of March 2003, the following stormwater permits were issued by DEQ to permitted facilities that have discharges in or near Johnson Creek: 11 construction stormwater permits, 13 industrial stormwater permits, three combined animal feeding operations or (CAFO that are administered by the Oregon Department of Agriculture including one dog, one mink, and one swine operation), two industrial hydrocarbon cleanup related permits, and one domestic sewage drainfield (DEQ 2003). This does not include permits pending or those that have expired. Construction stormwater permits are for sites greater than 5 acres, although the threshold was lowered to sites greater than 1 acre in December 2002. The industrial permits allow precipitation to contact raw industrial materials and runoff into surface waters only if best management practices and controls are in place. Two of the industrial permits are for clean up of petroleum-contaminated soils at RM 10.8 and groundwater at RM 15.3. There is also an active permit for a Water Pollution Control Facility (WPCF), in this case, a church and domestic drainfield at RM 18.2. WPCF permits authorize discharge to groundwater, but not surface water.
At the current time, there are no known estimates for the amount of stormwater that enters Johnson Creek from the direct stormwater outfalls. (See Data Needs in Section 2.11.2.)
In accordance with Clean Water Act (CWA) requirements, the Oregon Department of Environmental Quality (DEQ) issued municipal National Pollutant Discharge Elimination System (NPDES) permits to both Gresham and Portland and their co-permittees in 1995. These permits cover a five-year period and require the implementation of a stormwater management plan and submittal of annual reports. As of 2003, DEQ has received permit renewal packages from these jurisdictions but have opted to allow Gresham, Portland, and their co-permittees to continue functioning through an extension of their expired permits. Permit renewal will be completed by 2004.
Both Gresham and Portland are implementing management programs for the new state and federally mandated Underground Injection Control (UIC) program. In addition, Multnomah County has implemented a UIC program within Gresham.
Sanitary sewer systems within the watershed are mainly owned, operated and maintained by the Cities of Portland, Gresham, and Milwaukie. Parts of these systems are located within the floodway of Johnson Creek and several manholes are located within the stream channel. Sanitary sewerage within Portland (along with some combined flow) is conveyed by two pump stations within the watershed to the Columbia Boulevard Wastewater Treatment Plant. Sewage is conveyed through the watershed within Portland by 153,794 lineal feet of sewer pipe (Portland ESA, 2000). In Gresham, sewage is piped through 470,721 feet of sewer pipe and pumped to the Gresham Wastewater Treatment Plant on the Columbia River. Sewage from development in the upper watershed east of the Gresham UGB is treated in onsite septic systems as there are no sewer extensions allowed outside of urban areas. There are also some onsite septic systems still being used in certain areas of Milwaukie. Siting, development, and maintenance of onsite septic systems is in the jurisdiction of the DEQ, and the program for Multnomah County is administered by the City of Portland Bureau of Development Services. A new WWTP is under construction in the Kelley Creek subwatershed to replace a failing septic field in Happy Valley.
The roadway network is extensive in the lower and middle sections of the Johnson Creek watershed. There are more than 50 bridges that cross the main stem of Johnson Creek.
An estimate of total impervious surfaces from roadways throughout the watershed is presently not available. For a discussion of roadway culverts and fish passage barriers see Section 2.10 Biological Communities.
Much of the two lower sections of Johnson Creek (15 miles) are deeply channelized and confined. Most of the channelization, designed to control flooding, is the result of depression-era public works agencies, primarily the Civil Works Administration and the Works Projects Administration (WPA). At several locations along the stream, a new course was created and the stream channel was straightened, deepened, and simplified. Dikes were constructed to contain and control the stream at high flow. Beginning in 1933, streamside vegetation was removed, and the dikes and streambed were armored with basalt rocks. The intent was to remove wood and vegetation behind which flows ponded and to increase the flushing rate of the creek. This channelization and armoring has had important consequences for the stream.
The channelization throughout the lower 15 miles did not stop major flooding. The channelization substantially altered the creek's configuration and severly limited connectivity to its historic floodplain. These alterations have had long-lasting and marked effects on the physical habitat structure and hydrology of the watershed, constraining lateral movement of the stream almost entirely and increasing winter flushing to an extent that large wood and other structural diversity is almost non-existent. There are other reasons however, for the lack of large wood including lack of source material within the riparian areas and human activities of removal of vegetation.
The WPA crews also constructed new features such as a canal and waterfall above Tideman Johnson Park, a nearby fish ladder, an old Tacoma Street Bridge and many other rock walls, stairways and bridges. They also worked in Lower Kelley Creek and Crystal Springs Creek where they constructed ponds at Westmoreland Park and piped water from Crystal Springs Lake to create a casting pond (City of Portland ESA, 2002).
Adolfson performed a cursory water rights information query from the Oregon Water Resources Department (OWRD) web site: http://stamp.wrd.state.or.us/apps/wr/wrinfo/wrinfo.php.
Table 1 summarizes query results from the period 1900-2003 obtained for claims, permits, applications, or certificates currently listed for the Johnson Creek watershed:
Table 1. Water Rights including number of Claims, Permits, Applications, or Certificates within the Johnson Creek Drainage Basin
| Number of Claims Permits, Applications, or Certificates |
Characteristic |
Type |
Total flow (cfs) or volume (AC-FT)* for all claims, permits, applications, or certificates |
| 32 Claims |
Groundwater Registrations (GR) |
Wells |
15.17 |
| 65 Permits |
Groundwater (G) |
Wells |
62.03 |
| 53 Permits |
Surface water (S) |
Surface Water including creeks, streams, or springs |
31.51 (includes 12.0 cfs for Butler Cr. Reservoir and 6.0 cfs for Hessel Reservoir (Frank Schmidt Nursery) |
| 3 Applications |
Groundwater (G) |
Wells |
3.28 |
| 2 Applications |
Instream Flow (IS) |
Surface Water |
15.0 cfs – Crystal Springs 25.0 cfs – Johnson Creek |
| 4 Applications |
Ponds (P) |
Surface Water |
5.60 AC-FT |
| 23 Applications, Permits, or Certificates |
Reservoirs (R) |
Surface Water |
110 AC-FT |
* cfs = cubic feet per second; AC-FT = acre feet
Water diversions and withdrawals can have significant impacts on watershed hydrology. Increasing baseflows throughout the Johnson Creek watershed will be important for restoring hydrology to a normal hydrograph and to obtain properly functioning conditions. More research will be required to: 1) locate illegal water diversions and withdrawals, 2) identify areas for irrigation improvement; 3) assess alternatives for off-line systems; 4) contact holders to assess opportunities for instream water rights purchase; and 5) review and comment on new water rights applications.
