Virtual Watershed Interpretive Trail
Open to the public for self-guided exploration, hours vary by season. A schedule of monthly activities are show on our calendar. Tours and educational programs for groups provided upon request. For more information, please call : 503.632.2150.
The Watershed Interpretive Trail is designed to introduce you to some important ideas about watersheds and woodland resource management. Along the trail you'll find numbered signs that correspond to descriptions found in this brochure. To get the most out of the trail, stop at each signpost, read the entire description, and look carefully at the features that are described. Note that there are two major trail loops. Different features are highlighted in each loop, so both are recommended. The time needed to hike both loops, stop, read and view the various features, is about 2 hours.
What's a watershed? It's an area of land that collects rain and snow and discharges much of it to a stream, river, or Other water body. The specific water body of concern is what defines a watershed.
Most of the watershed for the stream at this point is land owned by neighbors upstream (about 500 acres). What happens on this neighboring land can affect the quality and quantity of water that flows here. Likewise, activities on the Hopkins Memorial Tree Farm can affect water that flows through properties downstream on its way to the Molalla River and beyond. Watersheds can thus link landowners and others in important ways, which points to a "good neighbor" approach to resource management.
Nature itself can be an important influence on watershed resources. Notice the beaver pond upstream. Flooding and slow drainage from such ponds can kill trees and other shading vegetation and raise water temperatures. Beaver may also contaminate water supplies with diseases like Giardia. On the other hand, new types of fish and wildlife habitat have been created by the pond, and it may also act as an effective sediment trap. Environmental change is common in nature. Carefully observing such change helps us keep human activities in perspective.
You're now standing in a riparian zone, the area of moist soils and related plant cover next to a stream or other water body. These areas often have important functions and values. Riparian trees or smaller plants can provide shade that helps keep stream temperatures cool. Wildlife may find abundant food and cover here. Trees and other large woody debris that fall into streams can create valuable pools for fish, and leaves from riparian plants provide food for insects that fish eat. Timber, forage, and recreational valuesalso may be high. Because of such values and the potential for affecting water and other resources, Oregon's Forest Practice Rules (Administered by the Oregon Department of Forestry) often require forest landowners to modify their management practices in riparian zones.
Along this Watershed Interpretive Trail you will notice white fiberglass rods marking the riparian management area. Markers are located 20 feet and 50 feet from the high water level of the stream channel. In Oregon, no vegetation within the first 20 feet of a stream - having the same size as the one here at Hopkins - can be disturbed. Between 20 and 50 feet from the stream, some management including limited tree removal, may be allowed. All roads must be located more than 50 feet from streams of this size.
On the other side of the stream you'll notice a large, old stump. Look carefully and you can see a rectangular "spring - board hole" in the stump. The old stumps you'll find along the trail show there was logging in this area several decades ago. This and other historical activity (e.g. farming, road building) no doubt had some effect on the riparian zone and seam channel seen here today. Keep in mind that technology and legal requirements were limited prior to the 1970's. Also, for a number of years, large woody debris was removed from stream channels in this region to help fish move upstream to spawn. Today, we recognize that this practice probably harmed fish habitat, and our knowledge of how to protect and enhance such watershed resources has improved greatly.
The stream meanders quite a bit here, showing channels are dynamic and often have areas of natural erosion and deposition that can shift over time. In most cases, it's best not to try to control these natural processes, unless property or other resources are threatened. Even then, special expertise usually is needed. Note that the roots of the cedar tree are helping to protect and stabilize the bank at the big bend of the stream.
Another 50 feet or so farther along, next to the trail, is a large cedar snag, or standing dead nee. Snags often are important habitat for "cavity nesting" birds and other wildlife that can be abundant in riparian areas. Eventually, they may provide large woody debris to stream channels. Cedar and other conifer snags and debris are particularly valuable to wildlife and fish because of their size and slow decay.
Here are some good examples of large woody debris in the stream channel. The debris downstream forms a Small dam that slows the water, which reduces channel scour and allows sediment to settle and be stored. In other locations, large logs or other debris may create cascades and large pools that benefit fish habitat. This debris dam has remained stable for some time, which allowed a conifer to seed in and grow in the decayingdebris to about 25 years of age before it died.
Several logs cross the stream here but don't affect the channel very much, except to provide a bit of cover. With time they will break up and fall into the stream, probably forming some pools. The moss and other plants on these logs show that over the years since they fell, the water level rarely reaches the tops of the logs. Such clues can help us estimate what this stream looks like during major storms, which is helpful when planning stream crossings or other activities near the channel.
You just crossed a small tributary that feeds into the main channel. Such streams may have only intermittent flows instead of carrying water throughout the year (i.e., perennial), and they often do not show up on maps. They can still influence the quality and quantity of the waters they feed into, so they shouldn't be ignored when planning management activities. This is especially important because many activities are done during the dry season, when a lack of water often make smaller tributaries hard to identify.
Notice the variable tree cover. Riparian areas usually have plenty of moisture and fertile soil for trees and other plants to grow well, but this can also create a lot of competition for space and light. If seedlings of trees like Douglas - fir that need direct sunlight were planted here for habitat or timber, they probably would not survive unless the competing vegetation was controlled in some way. Even seedlings of cedar or hemlock that can grow in shade may not survive, or they may take many years to outgrow the competition.
Here's a fine example of the scenic beauty that can be found along streams. Such beauty shows why hiking and other recreation is often concentrated near water bodies. Heavy use in attractive areas can sometimes cause problems such as waste disposal or erosion from trampled hiking trails. One way to reduce such problems is to locate trails and other places of heavy use some distance from streams, as we tried to do here. People can still greatly enjoy this area, yet the risk of impacts to the stream is very low.
Note the large fire scarred stump on the right side of the main trail that now follows an old road. Natural wildfires and prescribed burning for logging debris disposal or reforestation (by eliminating competing plants) have occurred throughout this region. When fires are hot enough to consume the duff layer (leaves, needles, twigs, etc.) that normally covers the soil, runoff and erosion may increase from sloping areas. Wildfire hazards can be reduced by using fire breaks (i.e., roads and other areas with little fuel) and by maintaining good access and a reliable supply of water (in addition to the stream, there are two ponds near the middle of this property). Prescribed burning can be scheduled during cooler or wetter periods to reduce the loss of protective duff, and areas near the streams or in very steep terrain can be left unburned.
Looking just a bit farther to the side of the trail opposite the stump, you may see a dirt bike trail that enters from the left. Unauthorized recreation sometimes causes soil and water problems. Sturdy gates can limit access by 4 - wheelers, but those on foot, horseback, or two - wheels (motorized or not!) can be difficult to control. Keep in mind that such problems may be unintentional, and visitors may simply need to know what you'd like them to do or not do. Signs or direct contact may be helpful.
At this point the old road turns and will soon cross the stream. If the road is used again for vehicle traffic, surfacing and drainage improvements probably would be needed, especially on sloping sections like this just above. Roads near streams can be a significant source of runoff and sediment, especially if drainage systems are not carefully designed and maintained. Drainage water should be quickly routed off the road surface to undisturbed areas where it can be absorbed by the soil. Gravel surfacing can reduce erosion from roads, especially if there's traffic during wet weather. Adding gravel can be costly. If a road will receive only light use, a grass seeded surface can be an inexpensive alternative.
Although this road was constructed many years ago, it follows a good layout. Even though it generally runs parallel to the stream, it is located well away from the channel and riparian area. Up ahead, where the road crosses the stream, it does so at a right angle (i.e., perpendicular to the seam). This keeps stream and riparian disturbance to a minimum, and reduces the chance of any runoff or sediment from the road getting into the stream.
Stream crossings are a key feature of many woodland road systems. The original crossing here used a 36 - inch culvert that was showing signs of decay and seepage through the fill. In 1996 it was replaced by this vented ford, which meets the current Forest Practices Rules for flow design (50 - year event) and fish passage. During very large storms, flows can overtop the crossing without erosion or other damage. A bridge or larger culvert could have been used, but much more fill would have been needed and total costs considerably higher.
Landowners who plan to build roads that cross streams may need to get help to comply with the law and avoid watershed impacts. Local offices of the Cooperative Extension Service and the Oregon Department of Forestry are among the sources of assistance. Detailed information about the vented ford, it's design, installation and cost, contact Forests Forever, Inc. or the OSU Extension Office in Oregon City.
Between LoopsIf you now head west on Up Creek Road (left), you'll soon reach the "Middle Loop" of the Watershed Trail. Along the way, be sure and see Stops 9 and 10. If you're short of time, you can turn right (east) and return to the main road (Grouse Hollow) via Carlson Road, which connects with the start of the Watershed Trail.
This location had a 36 - inch culvert like the original crossing at Stop 8, but it washed out during the February 1996 flood (note: the culvert moved downstream from this point about 100' during the flood). The failure probably was caused by the combination of an undersized pipe and inadequate installation. Some fill erosion around the pipe was seen long before the washout, apparently because it was not well compacted or protected with riprap when it was installed.
Keep in mind that even with the best road and crossing designs, upkeep will be needed to maintain good drainage and avoid erosion. For example, culverts should be inspected regularly for blockages or other problems. Grading (i.e., scraping and shaping the road surface) and ditch cleaning can help eliminate ruts and restore good drainage. Wet weather is an especially important time to inspect roads and to correct problems quickly before they cause damage or become much more difficult to handle.
The stream channel is only about 40 feet from where you are standing. Even in this open area, the brushy undergrowth almost fully covers the stream. Trees could be planted hereto provide a future source of large woody debris (the cedar on the far side will provide some debris), but along small channels like this shrubs often give enough shade to keep water temperatures cool. Grass and other plant competition would make reforestation challenging, and using chemicals or other weed control measures this close to the stream would require special precautions to protect water quality.
Because this road was constructed many years ago, its location near the seam is less than ideal. Upgrading the drainage system and running surface was begun recently along this road so that vehicle traffic will not add excess runoff and sediment to the stream. The new ditch on the uphill side of the road collects drainage water from the road and hillside. This water travels through plastic culverts under the road, like the one located here. The discharge water splashes against rocks placed at the outlet end of the culvert to slow its movement and settle sediment before reaching the stream. When - ever possible, water draining from forest roads should be routed to undisturbed areas to settle sediment. Another option is to construct a small settling basin to trap sediment from the road. Finally, roadside areas have been seeded with annual rye grass to protect the sop and prevent erosion. Seeding is usually most effective in western Oregon when done in the late summer and early fall.
The trail has been routed upslope around a property boundary. A comer of the neighboring property extends to this side of the stream. A new stream crossing might be needed if the neighbor wanted access to cut some timber or for other purposes. Because of the cost and possible resource impacts of new stream crossings, it might be better to talk to the neighbor about a reciprocal access agreement. Landowners can thus arrange a way to use each other's roads to access their property on both sides of the stream.
Neighboring landowners can make other arrangements to their mutual benefit. Contractors who do road maintenance (grading, ditch cleaning, etc.) may provide a price break when adjacent work avoids costs of moving heavy equipment. Likewise, the cost of culverts, rock surfacing, tree seedlings, chemicals, etc. may be less if a larger order is arranged among landowners. Talk with your neighbors; you may find you're thinking about doing some similar work. You might also be able to share valuable experience and ideas about woodland and watershed management, and perhaps work together to benefit both the watershed and you.
This area shows some contrasts between an upland hill slope and a riparian terrace. Dark, moist soils and red alder trees are found on the terrace. Low, flat areas like this often have a high water table (i.e., saturated soil is found close to the surface), which can limit the tree species that will grow successfully. For example, cedar or cottonwood may do well, but Douglas - fir may not. A larger area with a persistent high water table also may be a wetland, and may be subject to special management restrictions for resource protection. Soils high in moisture and organic matter are weak and can be easily disturbed by vehicle, foot or animal traffic. If timber is removed from an area like this, it may be best to keep harvesting equipment off the terrace and winch logs to it. Another option may be to wait until late summer when soils are driest and least likely to be disturbed.
Upslope was a failed reforestation project originally cleared and planted in 1980. Aside from the heavy plant competition, tree seedlings were damaged or killed by "boomers," small rodents also called mountain beaver. Boomers won't be found in the wet riparian area, but in the well - drained soils just upslope where they burrow underground. Trapping the boomers or protecting the seedlings may be needed to get trees to grow here. This area was cleared, again, in the summer of 1997 and is scheduled for replanting during the winter of 1998.
Notice the well - stocked red alder stand on the terrace near the stream. In some areas, riparian alder stands can affect water quality when leaves are shed in the fall. This is most likely on small streams when fall rains come late. Leaves mix with slow - moving water to form a "tea" rich in organic matter. This can be a problem for aquatic life if oxygen levels become low, and it can make water distasteful or unhealthy to drink. A strategy to convert riparian alder stands to conifers may be desirable where such water quality problems occur often. However, special riparian management plans must be approved before any harvesting, site preparation or reforestation activities can occur within 50 feet of this stream channel.
The stream channel has a low gradient (gentle slope) here, which slows the flow of water. The large woody debris slows the water further. Slow - moving water cannot carry as much fine sediment, which may explain why the stream bed is mostly fine - textured material. The soft, erodible bed material also allows the channel to meander quite a bit through this flat area.
Notice the larger conifers on the other side of the stream. Some, near the stream, will need to be retained for fish and wildlife habitat under Oregon's Forest Practices Rules. If other trees are harvested across the stream, it may be difficult and costly to construct a stable crossing here in this wet, soft soil. As mentioned, it may be best to arrange an access agreement with the neighboring landowner, or else use a crossing in a less sensitive location.
The larger logs and v - shape of the woody debris accumulation here should keep it fairly stable during high stream flows. In other cases, woody debris may shift or move downstream during heavy storms. Debris stability depends on the size and orientation of the pieces, as well as the size and flow of the stream. Some debris movement during storms is OK, but there may be problems if it reaches a culvert or bridge crossing. Also, steep channels may be severely scoured if there is a debris torrent. Guidelines are available to help judge the stability of woody debris in streams.
The moisture - loving alder tree is able to grow directly in the channel. It has even formed a pool with its roots that is helping trap sediment. When this tree dies, it will add more structure to the channel, although it will decay more quickly than the nearby cedar logs. Note, too, how a large cedar log has fallen down the opposite slope. Where such steep slopes border a stream channel, woody debris may be supplied by trees quite a distance upslope.
The channel here begins a transition to a steeper gradient and a coarser stream bed. The cobbles and boulders should be fairly stable even during high flows. There's also plenty of woody debris, which is trapping some of the sediment. The small cascades formed by the rocks and debris help aerate the water, which may be important if oxygen was reduced in the slow - moving section upstream.
Upslope is another area where trees are generally absent. Cost - share funds may be available to help landowners with reforestation or other watershed improvements. Local offices of the Oregon Department of Forestry and the Clackamas County Soil and Water Conservation District can provide details and assistance.
The gurgling water cascading through this area indicates an even steeper stream gradient. Large boulders are often found in such steep areas, because most fine material was washed away long ago, leaving behind a relatively stable channel. The boulders and the steep bank on the other side of the channel may indicate a major change in geology or soil type. Such changes may also be a key influence on the size and type of trees and other vegetation found here. Like Stop 6 in the East Loop, this scenic area could be very attractive for recreation. Remember that careful trail layout, fencing, or other approaches may be needed to protect the stream and riparian area from excessive disturbance.
End of the Trail
Think about the many features and contrasts in the stream and riparian area that you have seen along this trail. Even over a short distance, conditions and management considerations can change dramatically. This can make watershed management very challenging. It also offers a fascinating area for work and study exploring the vital links among natural resources and people.
The end of the Watershed Interpretive Trail doesn't mean you can't learn more about watersheds and resource management. Many publications, audio - visual programs, and other resources are available. In addition, educational programs and tours are held often by the Cooperative Extension Service, local chapters of the Oregon Small Woodlands Association, and other groups.
Watch for notices about future educational activities at the Hopkins Memorial Tree Farm. Detailed information - including this brochure
This trail and brochure were made possible by support from the Governor's Watershed Enhancement Board (GWEB) with funds from: the Oregon State Lottery, Clackamas Soil and Water Conservation District, Forests Forever, Inc., the Stewardship Incentive Program and the Oregon State University Forestry Extension Program. Special thanks go to Liz Dent, John Poppino, Gilbert Shibley, Abigail Romick, Ken Humbert, Terry Wertz and Aaron Bondi for their help in stream and watershed inventory, trail layout and brochure preparation. Paul Adams, OSU's Forest Watershed Extension Specialist, and Mike Bondi, OSU's Extension Forestry Agent in Clackamas County, directed the project and authored this brochure. For more information or to arrange educational activities at the Hopkins Memorial Tree Farm, contact the OSU Extension Office in Oregon City 503.655.8631.