Water Quality

Background

Water quality is assessed in terms of chemical, physical, and biological elements. The primary goal in assessing water quality is to identify the general condition, and to flag obvious areas of concern or deficiency.

There are a number of overlapping, often confusing federal and state regulations that influence standards for water quality in Rock and Richardson Creeks. The 1972 Federal Clean Water Act sets the overriding regulatory framework. Essentially, this law requires each state to set reasonable standards for each water body. It also asks states to list all rivers, lakes, and streams that fail to meet the standards. This is known as the 303(d) list, which is administered in Oregon by the Department of Environmental Quality (DEQ).

The State of Oregon has also established special status for the entire Clackamas Basin because it is an important drinking water source and provides critical habitat for many sensitive species of plants, fish and wildlife. This is known as the "Three Basin Rule," and limits new or increased point source discharges such as industrial or sewer outfalls.

Standards for streams are set based on "beneficial uses." The most demanding or sensitive beneficial use is the one that dictates where the standard is set. Beneficial uses for Rock and Richardson Creeks include domestic consumption, industrial supply, irrigation, livestock, salmonid and other aquatic habitat, and other wildlife. Of these, the requirements for salmonids tend to be the strictest. A complex set of standards applies to Rock and Richardson Creeks, as illustrated in the table below. The standards vary based on the time of year that salmonids may be spawning in the creeks.

Findings

Water Quality Standards*
Water Quality Parameter	Non-spawning Periods (mid-July to August)	Spawning Periods (August to mid-July)
Water Temperature	17.8° C (64° F)^a	12.8° C (55° F)^a
Dissolved Oxygen (mg/L)	8.0^b,c, 6.5^d, 6.0^e	11.0^{f, g} ,11.0^h
pH (units)	6.5 – 8.5	6.5 – 8.5
State of Oregon water-quality standards for water temperature, dissolved oxygen and pH for the Clackamas River Basin, Oregon (table modified from Carpenter, draft report). mg/L = milligrams per liter °C = degrees Celsius °F = degrees Fahrenheit ^a Based on the 7-day average of the daily maximum temperatures. ^b Based on a 30-day mean minimum concentration. ^c If conditions of barometric pressure, elevation, and temperature preclude achievement of the indicated concentration, then the 90% saturation standard applies. ^d Based on a 7-day minimum mean concentration. ^e Absolute minimum. ^f Absolute minimum, if intergravel DO is less than 8.0 mg/L. ^g If conditions of barometric pressure, elevation, and temperature preclude achievement of the indicated concentration, then the 95% saturation standard applies. ^h If the intergravel DO is greater than or equal to 8.0 mg/L.

Various studies of water quality indicate that there may be some problems in both Rock and Richardson Creeks. High temperature, low dissolved oxygen (DO), excess sediment, excess nitrates, and high levels of bacteria have been found in either Rock or Richardson Creeks at some point. These measurements have not been systematic or detailed enough to warrant 303(d) listing to date. Generally, water quality appears to be adequate for salmonids and other beneficial uses, but there are some indications that Rock Creek may be close to the edge, particularly with stream temperature. In addition, a recent study by URS Corporation for Clackamas County developed a predictive model for what may happen to each creek as a consequence of urbanization. This model predicted that sediment loads will increase more than six times, total phosphorus loads will increase more than three times, and total copper loads will increase by more than ten times (URS Corporation, 2000b). Water quality measurements to date have been sporadic and project driven, rather than systematic and long term. The table below summarizes key aspects of these studies.

While most major point sources of pollution are known (see map in Hydrology section), non-point sources are not well documented. Richardson Creek has a high level of nutrients, which cause algae blooms in the Clackamas River. The exact sources of nutrient inputs are not documented, but are likely to be a combination of agricultural and suburban lot applications of fertilizer. Likewise, while there is insufficient water quality monitoring data to indicate the presence of specific chemicals, herbicides and pesticides are likely to be having impacts on water quality and require further study. There are some indications, generally, that stream-borne pesticides may interfere with salmon migration.

Unexpected turbidity has been observed in Rock Creek during low water. The instances of turbidity have not been well documented, and the causes are not known.

The failure of the Safeway and Dairy Queen septic systems near Damascus is a highly visible water quality issue and has resulted in direct discharge of sewage into Richardson Creek.

Water Quality Studies in Rock and Richardson Creek
Study	Location	Dates	Parameters	Findings
ODFW	Lower Rock	Summer 1997–98	Temperature, DO, turbidity.	High summer stream temperature (15C), summer DO levels of 7–10 mg/L., problems with turbidity and sediment.
USGS	Lower Rock	Summer 1998	---	---
SWRP	Lower Rock	1992–2000	Water chemistry, macroinvertebrates, stream channel habitat, and riparian plant.	High concentrations of fecal coliform, high stream temperature, problems with DO.
Jeanna Leavitt	Lower Rock	Summer 1997	Summer stream temperature.	High summer stream temperature (17°C).
Pacific Rivers Council	Lower Rock and Richardson	1997–98	Macroinvertebrate sampling, IBI indexing.	Low diversity of macroinvertebrates (19 species), low to moderate IBI counts.
ODFW	Upper Rock	unknown	Visual survey of riparian conditions.	Bank erosion, sediment, lack of shade.
ODOT	Richardson	unknown	Septic tanks impacts.	High bacteria.
DEQ (Dames and Moore, 1992)	Richardson (near Damascus)	November 1989	Water Chemistry.	High levels of fecal coliform and streptococcus bacteria due to failure of Safeway and Dairy Queen septic systems.
DEQ	Richardson	1998	Potential candidate for Oregon 303(d) list of degraded streams based on sediment and nutrient problems.	Insufficient data to make the 303(d) listing.
Sources: Oregon Department of Environmental Quality; Oregon Department of Fish and Wildlife; Oregon Department of Transportation; Student Watershed Research Project; United States Geological Survey

Information gaps

No clear conclusions can be drawn from the data available.
No trend line is apparent.
Variability of data over time is unknown.
The full extent of water quality problems is not known.
The sources or causes of apparent problems have not been clearly identified. Recommendations for the Basin Council
Design and implement a systematic and long term monitoring program for water quality. Given the urbanization that is planned for this area, this monitoring should be the responsibility of the governing jurisdiction(s) rather than the River Basin Council. However, the Council could be a partner in this effort.
A proactive approach to an urbanization process that protects the aquatic ecosystem should be crafted. This means a working partnership between the County, Council, landowners, and developers that employs state-of-the-art techniques (i.e. wide stream buffers, sediment ponds, detention and treatment areas, grass swales, narrow streets, development of an urban stream canopy, etc.).
Identify logical areas to immediately protect or restore rather than waiting for additional water quality data.
Coordinate with Clackamas County Service District #1 and Clackamas County Soils District to repair and replace failing septic systems.

Hydrology and water use

Background

Rock Creek drains a watershed with a total area of close to ten square miles (6,278 acres) and is the lowest contributing subbasin to the Clackamas River. Just upstream on the Clackamas River is the Richardson Creek confluence. The Richardson Creek watershed is less than half the size of the Rock Creek watershed with a drainage area of little more than four square miles (2,709 acres). The accompanying Stream Profile map shows the general topography of both watersheds and the relative elevation profile of each mainstem.

A combination of ground water discharge and direct surface flow of water from precipitation feed Rock and Richardson Creeks and their tributaries. The volume and rate at which water flows within these streams is influenced not only by precipitation, but by the rate of local groundwater recharge and extent of poorly drained or impervious surfaces. Groundwater bodies are recharged by infiltration of precipitation during the fall, winter, and spring months. A portion of groundwater is discharged as seepage into perennial streams, providing a relatively steady rate of flow in Rock and Richardson Creeks. The survival of salmonids in these watersheds depends on these steady moderated flows.

Average Annual Flow and 50-Year Flood Flows
	Rock Creek	Richardson Creek
Average Annual Flow (cfs)	21	7.5
50-year Flood	1,216	495
Watershed Area (square miles)	10	3.6
Source: Dames and Moore, 1992

In general, removal of the tree canopy cover and underlying organic humus layer affects rainfall runoff processes by reducing interception and infiltration rates (Dunne and Leopold, 1978). The water balance of an area is affected by altering the vegetation cover. Precipitation in the form of rainfall or snowfall is intercepted by trees and vegetated areas. Water is stored in the leaves, stems and branches of the vegetation. Water moves through the vegetated cover through stemflow and throughfall, which provides water to the soil surface at a moderated rate. The upper organic and humus layers in the soil provide temporary water storage and allow infiltration of water into the soil to take place more gradually. Without vegetation cover and organic layers to moderate the rate of infiltration, the soils become quickly over saturated, turn to mud and become overland flow.

Average annual rainfall ranges in the Rock and Richardson watersheds ranges from 53 inches in the higher elevations to about 45 inches in the lower elevations, near the confluence with the Clackamas River. December, January and February are the wettest months and July, August and September are typically the driest.

Findings

USGS Flow Data for Rock Creek near Troge Road
Rock Creek flow data

The hydrologic pattern of these two watersheds has been considerably altered from earlier natural conditions. By the late 1800s, human influences had already altered the hydrologic regime as European settlers converted forestland to agriculture, pastureland, and orchards. Logging also took place on the relatively steep slopes of the surrounding forested buttes and valley foothills. Today, the hydrologic character of these basins are impacted by current land uses such as eroded streambanks from livestock grazing (Apostol et al., 2000), fragmented riparian corridors, water quality problems and altered stream flows.

The broad pattern of development has fragmented natural vegetation and impacted the water and habitat quality of the riparian zones. Some relatively large patches of upland forest habitat and vegetated riparian corridors are still intact. The largest is approximately 1,190 acres of contiguous forest located on Scouter Mountain. This area may provide an important groundwater recharge function, augmenting flows in the lower portions of Rock Creek.

The primary significant aquifers in the Rock and Richardson area are the Troutdale Formation and the Boring Lava. The Troutdale Formation includes multiple layers of permeable and less permeable layers resulting in relatively high degree of horizontal movement of water and large amounts of natural discharge through seeps and springs. The Troutdale Formation is overlain in places by the Boring Lava, which generally sits above the regional water table (USGS, 1965). Perched groundwater within the Boring Lava may be significant as a source of flow into Rock and Richardson Creeks. If so, it will be critical for salmonid habitat protection and restoration to maintain, if not improve the rate of infiltration of precipitation into the Boring Lava. Moreover, the Troutdale Formation contacts the surface in Richardson Creek and is likely to influence water quantity and flow in that stream system. Over two-thirds of the soils in Richardson Creek are well or moderately well drained, indicated that the creation of impervious surfaces through urbanization may have significant consequences for stream flow in Richardson.

Rock Creek stream profiles Groundwater is also withdrawn directly through wells, which may be lowering the water table and reducing flow into streams. The accompanying map shows only the major groundwater wells, along with known point sources of pollution and discharge.

The hydrologic regime of Rock Creek and Richardson Creek basins will be further altered by future urbanization. Some of the anticipated changes include an increase in the amount of impervious areas resulting from paved roads, parking lots, housing developments, shopping malls, commercial and industrial developments, etc. Without sensitive planning and development practices, increase in impervious areas will likely result in a significant increase in the volume of surface water runoff, peak flow rates, low summer flows, water storage capacity, and inputs of pollutants to nearby stream systems. These changes in hydrologic conditions would be extremely deleterious to salmonid populations.

Stream flow characteristics

Empirical stream flow in Rock and Richardson Creeks is currently very limited. Average annual streamflow in Rock and Richardson has been estimated to be 21 cubic feet per second for Rock Creek and seven and one half cubic feet per second for Richardson Creek, based on correlation with measured flows from nearby Johnson Creek and other regional stream flow data (Dames and Moore, 1992).

The only stream gauging station installed in either Rock Creek basin or Richardson Creek basin was a US Geological Survey station near Troge Road, which recorded flow data from 1957 to 1966. The average annual peak flow for this period was 170 cubic feet per second. The chart below indicates the variation in flow during the eight-year period.

Clackamas County Water Environment Services contracted with URS Corporation to conduct a hydrologic analysis of the Rock Creek basin in order to determine peak flow characteristics and identify flooding problems. Although the results were not available to incorporate in this assessment, the URS study used a proprietary version of EPA's Stormwater and Wastewater Management Model (SWNN) to assess the surface water drainage system of the basin. In order to calibrate stream flow measurements, however, model results need to be compared with empirical stream flow measurements, which are lacking.

Flood activity

Detailed knowledge of past flood activity within Rock Creek and Richardson Creek basins is also limited and requires further investigation. The most severe recorded floods within the past 100 years occurred in 1964 and 1996.

Rock Creek water supply The proposed future urbanization of these two watersheds will have an effect on peak flows as well as low-flow conditions. The 2000 study by URS Corporation is designed to develop a hydraulic stormwater analysis of Rock Creek that will evaluate the implications of future development on the capacity of the existing drainage system.

As urbanization accelerates the proportion of impervious surface in the watershed will increase sharply. Without careful planning and implementation of significant mitigations, new development will result in a significant increase in the volume and peak flow rates of urban runoff.

Information gaps

The influence of the Troutdale Formation and the Boring Lava on water flow regulation in Rock and Richardson Creeks in not entirely understood.
The extent and effect of groundwater wells on the water table and subsequently on stream flow is unknown.
There is a lack of consistent empirical data on stream flows in both streams.
The full extent of the floodplain has not be delineated or mapped in either watershed.
The relative value of different areas of the watersheds for infiltration and storage of precipitation is not completely understood.

Recommendations for the Basin Council

Work with partner agencies to design and implement a systematic and long term monitoring program that develops and empirical baseline for water flows.
Work with the County, Council, landowners, and developers to develop a proactive approach to stormwater runoff issues associated with urbanization process including state-of-the-art techniques that reduce impervious surfaces, delay the introduction of stormwater into streams and direct stormwater directly into groundwater recharge.
Work with planning agencies to protect areas with high existing values for capture and infiltration of precipitation, including the Boring Hills and well and areas with moderately well drained soils.