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Lotic Overview Gen Plan 310
- 1. RIPARIAN FUNCTIONS FOR A GENERAL PLAN Sherman Swanson UNR
- 5. NATURAL RIPARIAN RESOURCES VEGETATION WATER SOIL/LANDFORM
- 11. Riparian PFC Team Approach!! Hydrology Soil Science/Geomorphology Plant Ecology Fish & Wildlife Biology Landowner/Permittee
- 21. PFC?
- 22. PFC?
- 25. From Rosgen 1996 .
- 26. Slope: < 2 % W/D: < 12 Sinuosity: > 1.5 Valley: broad/meadow E6 type channel. Silt / clay dominated substrate.
- 27. C4 type channel. Gravel-dominated substrate. Slope: < 2 % W/D: > 12 Sinuosity: > 1.4 Valley: broad/terraces
- 32. STREAM RECOVERY PFC Vulnerable Time Decision Space Fisheries Values Livestock Values Recreation Values Wildlife Values Watershed Values Desired Condition Bare Ground PNC
- 33. Current Conditions Desired Future Conditions
- 34. Current Conditions Desired Future Conditions PFC
- 37. STREAM RECOVERY
- 40. KGC-11 KGC-11 Bear Creek 1977
- 41. -40 -20 0 20 40 60 80 100 Date Temperature (Degrees F) Air Water Difference Difference in Air & Water Temperatures Bear Creek - Central Oregon 1976 IFLM-22 8-Aug 10-Aug 12-Aug 14-Aug 16-Aug 18-Aug 20-Aug 22-Aug 24-Aug 26-Aug 28-Aug 30-Aug
- 42. KGC-12 21 Years Later
- 43. 0 20 40 60 80 100 120 7-Aug 9-Aug 11-Aug 13-Aug 15-Aug 17-Aug 19-Aug 21-Aug 23-Aug 25-Aug 27-Aug 29-Aug 31-Aug Date Temperature Degrees F Air Water Difference Difference in Air & Water Temperatures Bear Creek - Central Oregon 1998 IFLM-23
- 44. QUIZ
- 48. 1 2 3
- 78. NON-LINEAR TIMELINES The power of drought – For allowing vegetation to encroach into a stream The power of Floods – For moving sediment, building banks, forming channels The power of disturbance – for reinitiating succession
- 80. INVENTORY ALL STREAMS UTILIZING PFC PROCESS Modify Management Strategy FAR w/Downward Trend Or Non- Functional Attain RMOs Continue Monitoring RMOS Upward Trend Continue Management Strategy PFC Or FAR w/Upward Trend Continue Management Strategy Static/Downward Trend Modify Management Strategy Monitor RMOS Monitor “NOs” From Checklist Modify Management Strategy Static/Downward Trend Attain PFC Continue Management Strategy Continue Monitoring (Iinclude RMOs) Upward Trend
- 82. STANDARD CHECKLIST -- Hydrology YES NO NA 1) Floodplain above bankfull is inundated in “relatively frequent” events 2) Where beaver dams are present, they are active and stable 3) Sinuosity, width/depth ratio, and gradient are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region) 4) Riparian-wetland area is widening or has achieved potential extent 5) Upland watershed is not contributing to riparian-wetland degradation
- 83. 1.) FLOODPLAIN ABOVE BANKFULL IS INUNDATED IN “RELATIVELY FREQUENT” EVENTS BANKFULL YES
- 84. 1.) Floodplain above bankfull is inundated in “relatively frequent” events NO BANKFULL NO
- 85. 2.) Where beaver dams are present they are active and stable YES BEAVER DAM
- 86. 2.) Where beaver dams are present they are active and stable BEAVER DAM NO
- 87. 3.) Sinuosity, width/depth ratio, and gradient are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region) NEW CHANNEL OLD CHANNEL NO
- 88. 3.) Sinuosity, width/depth ratio, and gradient are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region) YES
- 89. 4.) Riparian zone is widening or has achieved potential extent . YES NO
- 90. 5.) Upland watershed is not contributing to riparian-wetland degradation NO? YES
- 91. -- Vegetation YES NO NA 6) There is diverse age-class distribution of riparian-wetland vegetation (recruitment for maintenance/recovery) 7) There is diverse composition of riparian-wetland vegetation (for maintenance/recovery 8) Species present indicate maintenance of riparian-wetland soil moisture characteristics 9) Streambank vegetation is comprised of those plants or plant communities that have root masses capable of withstanding high-streamflow events 10) Riparian-wetland plants exhibit high vigor 11) Adequate riparian-wetland vegetation cover is present to protect banks and dissipate energy during high flows 12) Plant communities are an adequate source of coarse and/or large woody material (for maintenance/recovery)
- 92. 6.) There is diverse age-class distribution of riparian-wetland vegetation (recruitment for maintenance/recovery) YES NO
- 93. 7.) There is diverse composition of riparian-wetland vegetation (for maintenance/recovery) WHITETOP YES NO
- 94. 8.) Species present indicate maintenance of riparian-wetland soil moisture characteristics NO BLUEGRASS RUSHES/SEDGES YES
- 95. 9.) Streambank vegetation is comprised of those plants or plant communities that have root masses capable of withstanding high stream flow events NO
- 96. 9.) Streambank vegetation is comprised of those plants or plant communities that have root masses capable of withstanding high stream flow events NO YES
- 97. STABILITY
- 98. ROOT MASS
- 99. 10.) Riparian-wetland plants exhibit high vigor NO YES
- 100. 11.) Adequate vegetative cover is present to protect banks and dissipate energy during high flows YES NO
- 104. 12.) Plant communities are an adequate source of coarse and/or large woody material (for maintenance/recovery) NO
- 105. 12.) Plant communities are an adequate source of coarse and/or large woody material (for maintenance/recovery) YES
- 106. -- Erosion/Deposition YES NO NA 13) Floodplain and channel characteristics (i.e., rocks, overflow channels, coarse and/or large woody material) are adequate to dissipate energy 14) Point bars are revegetating with riparian-wetland vegetation 15) Lateral stream movement is associated with natural sinuosity 16) System is vertically stable 17) Stream is in balance with the water and sediment being supplied by the watershed (i.e., no excessive erosion or deposition)
- 107. 13.) Floodplain and channel characteristics (i.e., rocks, overflow channels, coarse and/or large woody material) are adequate to dissipate energy YES NO
- 108. 14.) Point bars are revegetating with riparian-wetland vegetation YES POINT BAR NO POINT BAR
- 109. 15.) Lateral stream movement is associated with natural sinuosity YES NO
- 110. 16.) System is vertically stable YES NO
- 111. 17.) Stream is in balance with the water and sediment being supplied by the watershed (i.e., no excessive erosion or deposition ) NO YES
- 112. 17.) Stream is in balance with the water and sediment being supplied by the watershed (i.e., no excessive erosion or deposition ) NO
Notas do Editor
- 03/22/10 This photo is to have something on the screen when people enter the room. For this purpose, the first photo could also be used. With this slide the host can make introductions and cover logistics such as location of restrooms, etc. The host or coordinator should also introduce him/herself and explain briefly why the Cadre is here, what we hope to accomplish in the class (generally over two days). Also, ask each participant and Cadre teacher to introduce themselves and tell us why they are here, what they hope to learn in the class.
- 03/22/10 The slide is self explanatory. However, physical functioning can be contrasted with values-based assessments such as habitat for any one species and with complete biological functioning, a thought process that quickly confuses values and successional process or extent. It cal also be pointed out that PFC assessment adds value to all the other inventory, assessment and monitoring data by making it more interpretable.
- 03/22/10 Too often there is not sufficient personnel, time, or funding to address all the riparian management opportunities. PFC assessment, by identifying areas at risk, helps sort out what is important from what is unimportant even if it appears urgent. Of greater utility, PFC assessment identifies specific reasons why an area is at risk and thus helps determine the management actions that are needed to address the problems.
- 03/22/10 Analogous to PFC assessment, a doctor commonly uses qualitative observations to make a diagnosis based on libraries full of well documented quantitative science. Additional tests or consultations with other specialists may be needed to increase confidence or address remaining questions. Monitoring protocols may attempt to standardize data collection and be all inclusive, addressing anything a manager might want to know. Such protocols become quite expensive because they are complex and time consuming. There is the additional problem of data interpretation. PFC helps focus management and monitoring on solving problems and meeting objectives.
- 03/22/10 Those of you familiar with a three legged stool will soon grasp the fact that a failure in any one of these legs would soon lead to a fall. Vegetation in a riparian area grow there because of the water and the soil that stores water and nutrients. The roots of those plants bind that soil into an armored structure that defines the channel or shore and the shade and debris from the vegetation further modifies the water environment. Riparian soils were generally carried in by flowing water, meaning they could be eroded away by flowing water were it not for the plants and the land forms that buffer those forces. The soils provide a very effective storage vessel for seasonal or occasional water and nutrients carried in by water. Yet saturation changes soil chemistry, making it suitable for riparian plants.
- 03/22/10 The definition of PFC gets to the heart of the assessment process and we will keep referring to it.
- 03/22/10 Form the combined functions of the vegetation, landform, and large woody debris, we get many resources that people value. We all benefit from properly functioning riparian areas. This makes riparian management saleable to people from all walks of life.
- 03/22/10 Some riparian areas function, but a soil, water, or vegetation attribute makes them susceptible to degradation and puts them at risk. Them may blow out, unravel, or cross a geomorphic threshold during a big event. A big event such as a 25 year flood. If they were in properly functioning condition, this should not occur.
- 03/22/10 Some riparian-wetland areas are clearly not meeting the PFC definition. They lack the vegetation, landform, or large woody debris needed to dissipate stream energies associated with higher flows, filter sediment and capture bedload, aid in floodplain development, improve floodwater retention and groundwater recharge, and stabilize streambanks.
- 03/22/10 Therefore they do not provide the benefits of properly functioning systems.
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- 03/22/10 This stream is high up in the mountains and it tumbles over big rocks. Riparian vegetation is present, but is not the major stability factor. Because PFC is rated for the potential of each area, considerations for this area should be quite different from systems elsewhere on the mountain or further down the valley.
- 03/22/10 Here too we have rocks and riparian vegetation. For its setting does it meet the definition for pfc?
- 03/22/10 Beavers played a keystone species role in the formation of many valley bottoms. By damming streams and capturing sediment, they helped form the floodplains and determined the soils and future plant communities. Big changes happen when unstable dams wash out.
- 03/22/10 We have some tools to help us sort through the questions concerning condition and potential (Rosgen and PFC); plus channel evolution models can help us recreate the steps the channel went through to get where it is today and also to help us understand what it is now capable of.
- 03/22/10 The Rosgen stream types that are most prevalent in pasture or range settings and whose morphology is maintained primarily by vegetation are C and E type channels.
- 03/22/10 E type channels are vegetated on both sides of the channel; are deeper than wide; and are quite sinuous. E type streams are located in a variety of land forms including high mountain meadows, alpine tundra, and broad alluvial valleys with well developed floodplains. E Type channels are hydraulically efficient and maintain high sediment transport capacity therefore mid-channel bars or pointbars are NOT expected. Substrates range from silt/clay to cobble and banks are stabilized primarily with extensive riparian or wetland vegetation that have dense, extensive root systems.
- 03/22/10 Rates of lateral adjustment are influenced by the presence and condition of riparian vegetation. Susceptible to both lateral and vertical instability caused by direct channel disturbance and changes in the flow and sediment regimes of the contributing watershed.
- 03/22/10 Soils (boulders, cobbles, bare gravels to facilitate establishment): water velocity is greater and plants must have strong, rebar like roots to survive high flows.
- 03/22/10 Capability is something less than potential, and is a result of long-term human changes on the landscape. It is important to note that these factors are different than natural limiting factors (e.g. badlands, canyon lands). Capability does not apply to uses such as grazing, farming, recreation, and timber practices which can be changed, While these uses can affect the condition of a riparian-wetland area, they do not have to prevent it from achieving potential. We have developed many tools for successful management of land uses. Capability only applies to constraints the land managers cannot eliminate or change through a management action. The above definitions are important aspects of the PFC methodology. The PFC tool is designed to assess if the physical elements (abiotic and biotic) are in working order relative to an areas capability and potential. If a particular riparian area does not have the potential or the capability to provide a specific attribute it would be rated as not applicable
- 03/22/10 Rosgen C3 Rivers normally develop a veneer of fine sediment across the top of the coblely bed material. However, this area has lost that veneer and it will not regain it because it is downstream from reservoir. Capture of fine sediment by reservoir has altered the ability of the Truckee River to build point bars etc. that include the fine sediment. As such the point bars seen in the picture are coarse textured. “Potential” of Truckee River has been altered and this slide is an example of “Capability” .
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- 03/22/10 When riparian areas do not function properly, they repeatedly suffer the consequences of high flows and have to start over as they begin to provide resource values. Once they function properly, managers can operate with flexibility in a decision space where they can optimize based on values. What is best for one resource user may not be best for another, but none of them are well served without the foundation of PFC
- 03/22/10 Every PowerPoint presentation has to have some “cute” graphics and here’s mine! Basically, what we’ve had before is a wall between where we are now and where we want to go. Using techniques we’ve typically used to-date we can’t see over the wall and by the time we’ve laboriously crawled over the wall much valuable time has been lost and many species don’t have all that much time.
- 03/22/10 A properly completed PFC assessment can provide a door through which we can only get an early peek at what is actually possible in the way of desired conditions but also allows us to more quickly move from current conditions to desired conditions without expensive dead ends.
- 03/22/10 Just remember PFC does not equal desired future conditions nor does it replace legal requirements. What it is, is a very valuable tool which supports and facilitates meeting all of these.
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- 03/22/10 These figures provide an example of the relationship between PFC and vegetation community succession for one riparian area (it may be different for other areas). In this example, assuming succession continues uninterrupted (states A – E), the channel will evolve through some predictable changes from bare ground to potential (in many real life cases this may not be as linear as shown). Once the riparian area is functioning properly, various resource uses can be sustained and desired future conditions depend on which resource values are most important to the people involved.
- This data was put together by Erv Cowley BLM Boise State office from some streams in southern Idaho. As things degrade, channel and water quality are the last attributes to show change. Again this shows that these two attributes are not the best items to determine whether management is working on a short term basis.
- 03/22/10 This graph presents some information of interest when choosing appropriate indicators. This graph doesn’t depict data from any one particular place but rather represents a compilation of the experience of Erv Cowley of the BLM Idaho State Office and several colleagues. As such, the time frames are general rather than specific but they are pretty close. Notice that if our management is going to be successful then herbaceous vegetation should begin showing an upward trend in about 3-5 years. Woody vegetation, if within the site potential, should begin to show an upward trend in 5 – 15 years. The slower responding channel features and water quality won’t begin to show change for about 20-25 years – and then if you’ll recall the Power Curve I showed you earlier, we still can’t prove it’s actually on an upward trend this early! But, it will be and we can prove it by watching these quicker responding indicators.
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- 03/22/10 Now we will have a pop Quiz! I will show you three slides and I ask you which of these areas would you invest in first? What would you try to accomplish and why?
- 03/22/10 Slide one: After viewing all three slides and waiting for responses, note that this area is incised, but it has been so for a considerable time and has developed space for a new floodplain. With riparian vegetation, first colonizers and then stabilizers, this riparian area will bounce back and become functional in just a few years. All it takes is management to allow the vegetation to respond appropriately.
- 03/22/10 After time for viewing and response, note that this area was once beautiful and productive with lush forage and willow as well as stream habitat. Now that it has deeply incised, it is highly unstable. The green next to stream is from chunks of sod that fell off the bank above. The concentration of energy and the erodible soil here makes this a risky and very expensive place to do restoration work. Often people recognize that the forces are too great for vegetation alone to provide stability and they put in dams to bring the water up. However, such dams often wash out. Water that is put onto the old floodplain, now terrace, will have to go back to the channel and that is where a headcut may bypass the dam. Eddy currents below the dam can also accelerate bank erosion. In Rodero Creek where seventy of these were put into a seven mile length of stream, in order to take total control, much sediment was captured. However many of the dams were in danger of failing only a few years later. If the banks are sloped and stabilized as some people do with rip rap, it may pickle the system into a very different sediment-transporting stream type than the meandering and dynamic stream that was originally in this wide valley with an accessible floodplain. Creation of a new channel on the old floodplain while turning this one into a series of ponds has been tried in some areas and the technology holds much promise. However, the new channel will have to be designed with the essentials it needs for proper functioning condition.
- 03/22/10 What a beautiful riparian area. But notice the high un-vegetated gravel bar. This indicates a problem. It may be caused from somewhere high up the stream that is depositing large amounts of sediment into the stream. Possibly that is where we want to go first as we seek to understand what is driving current dynamics. Problems could also be a caused by a head cut or incision beginning to form downstream (see top of slide).
- 03/22/10 So which of these three is top priority for the first investment? 3. Because it is functioning but at risk. It would be a real shame to lose the functionality of this riparian area. 1. Is also a good investment because it is ready to heal with a minimum investment of altered livestock management. 2. Although commonly the type of situation watershed dollars are invested in, this is probably the lowest priority because of the tremendous expense and risk.
- 03/22/10 This photo is to have something on the screen when people enter the room. For this purpose, the first photo could also be used. With this slide the host can make introductions and cover logistics such as location of restrooms, etc. The host or coordinator should also introduce him/herself and explain briefly why the Cadre is here, what we hope to accomplish in the class (generally over two days). Also, ask each participant and Cadre teacher to introduce themselves and tell us why they are here, what they hope to learn in the class.
- 03/22/10 This is a design diagram for a plug and pond project where the incision will be converted into a series of ponds (light blue) and the stream will be induced to flow across the terrace in an old abandoned channel (dark blue).
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- 03/22/10 By learning about riparian areas people, especially those who have worked in interdisciplinary teams, can often see a chain reaction of management effects. Thinking through this chain reaction, helps a person think about the time scale and the important attributes for setting objectives. There is nothing sacred about the % numbers used in this list. After taking time for some discussion of this, the next slide offers some help in answering the question.
- 03/22/10 Short term monitoring often focuses on the management actions. While these considerations are not objectives for the resource, they often trigger management actions or provide an indication of relative success in implementing a management action plan. Resource objectives describe an attribute of the resource that results from the planned management. Generally these attributes are easily measured even if the goal is more complex. Selection of the best attribute for an objective depends on the time frame for adaptive management. While riparian proper functioning condition (PFC) is considered the foundation for the values-based desired future condition, PFC is not a monitoring protocol because it is not quantitative. Once management has progressed the riparian area to proper functioning condition, the desired future condition becomes the focus for selecting attributes for monitoring as objectives. Try to select attributes that do not vary widely especially for reasons not related to management.
- 03/22/10 Management can adapt whenever sufficient knowledge motivates a change. In the short term, immediate effects are a key to interpret whether the management that year resulted in what was expected. With time vegetation begins to recover through reproduction and expansion, especially on the greenline where water is available. The vegetation leads to sediment deposition and to more vegetation. The combination of vegetation and channel form ultimately lead to additional changes such as water quality, fish habitat, etc.
- 03/22/10 Management can adapt whenever sufficient knowledge motivates a change. In the short term, immediate effects are a key to interpret whether the management that year resulted in what was expected. With time vegetation begins to recover through reproduction and expansion, especially on the greenline where water is available. The vegetation leads to sediment deposition and to more vegetation. The combination of vegetation and channel form ultimately lead to additional changes such as water quality, fish habitat, etc.
- 03/22/10 Management can adapt whenever sufficient knowledge motivates a change. In the short term, immediate effects are a key to interpret whether the management that year resulted in what was expected. With time vegetation begins to recover through reproduction and expansion, especially on the greenline where water is available. The vegetation leads to sediment deposition and to more vegetation. The combination of vegetation and channel form ultimately lead to additional changes such as water quality, fish habitat, etc.
- 03/22/10 Management can adapt whenever sufficient knowledge motivates a change. In the short term, immediate effects are a key to interpret whether the management that year resulted in what was expected. With time vegetation begins to recover through reproduction and expansion, especially on the greenline where water is available. The vegetation leads to sediment deposition and to more vegetation. The combination of vegetation and channel form ultimately lead to additional changes such as water quality, fish habitat, etc.
- Objectives should be based on the CURRENT and POTENTIAL condition of the site and allow for adjustments due to climatic conditions, monitoring methods, and ADAPTIVE MANAGEMENT . PFC or other assessment methods should be used as guides to develop objectives.
- 03/22/10 I’ve just shown vegetation as an example of potential indicators and many times it is very useful. However, other indicators such as mechanical bank damage, upstream watershed conditions, etc, may also be useful and necessary indicators. A properly done PFC assessment will help immensely in the task of choosing appropriate indicators rather than just monitoring everything and then digging for the pony at the bottom of the pile.
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- Perhaps this person regrets building the house next to the beautiful river. Perhaps insurance has allowed the house to be built back on the same floodplain. Does the requirement for flood insurance in a floodplain help or hinder?
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- A practical example of this is found below a reservoir where degradation occurs without the sediment load and possibly with extended periods of high flows. This meandering stream below a reservoir once kept this meadow so saturated, mesic forbs would have drowned. Without a continued supply of new sediment, the hungry water removes channel materials. All erosion is net erosion. With time, the channel is sinking into the meadow, slowly becoming an incised gully inspite of the fact that it is within a grazing exclosure.
- Unfortunately Lane did not have the advantage of our recognition of the importance of riparian vegetation providing roughness to slow water and dissipate energy. We also recognize the importance of vegetation for stabilizing banks, important to keep active channels narrow and pipe-like to transport sediment – OR NOT. When the flood channel becomes pipelike from incision, it changes rapidly and a channel without floodplain access, without form roughness, and without riparian vegetation roughness produces a surplus of sediment for upstream and a lowered base level for accelerated erosion upstream.
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- 03/22/10 Management can adapt whenever sufficient knowledge motivates a change. In the short term, immediate effects are a key to interpret whether the management that year resulted in what was expected. With time vegetation begins to recover through reproduction and expansion, especially on the greenline where water is available. The vegetation leads to sediment deposition and to more vegetation. The combination of vegetation and channel form ultimately lead to additional changes such as water quality, fish habitat, etc.
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- 03/22/10 This step by step flow chart identifies the connection between PFC assessment, resource management objectives, ongoing management and recognizing the need to change management.
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- 03/22/10 The first part of the checklist features attributes concerning water and its movement as influenced by floodplain access, obstructions, riparian and channel form and pattern, and watershed conditions.
- 03/22/10 Bankfull channels are constructed by the stream to fit the normal high flows, the flows that occur at least once in an average year and a half. Flows bigger than this should begin to flood over a floodplain in those settings where the valley is wide enough for the stream to develop a floodplain.
- 03/22/10 Although this stream once had a floodplain, it is now a terrace that rarely if ever floods. All flood water, sediment, and energy are contained inside the gully where the bankfull channel is so unstable that it is wide and shallow below steep vertical flood channel banks. Often incised streams begin to form a new floodplain inside the gully. These should be noted as should the fact and magnitude of the incision.
- 03/22/10 In places where there are no beaver dams, this attribute is rated as NA, Not applicable. In this case there are plenty of willows for the beavers to use in feeding and in maintaining the integrity of their dam(s). The best dams are built by beavers that use mud to fill in the spaces in their dams. Dams built by mudders can sustain willows etc. and the roots of woody species help stabilize the dam as the other wood rots out.
- 03/22/10 Beaver dams that are made without willows or other riparian woody vegetation are not sustainable. These beavers used sagebrush and juniper wood rather than species that resprout and grow quickly.
- 03/22/10 This river once had the meanders and floodplain access to sustain itself along with the riparian vegetation that kept it functioning. Channelization has ruined all that. Notice how the old channel spells out I. O. U.
- 03/22/10 Although not very sinuous, this channel does not have the potential to be very sinuous. Its step-pool structure is appropriate for the landscape setting in which it is found.
- 03/22/10 Riparian areas can widen by either narrowing the channel, forming new vegetated floodplain out of old channel bottom areas, or by elevating the water table with resistance to fast flow. Recovering streams may do both. If the riparian areas is widening, but han not yet reached its potential the answer is yes. If they have quit widening, but have reached their potential, the answer would still be yes.
- 03/22/10 Notice how this question is worded so that all the positive responses are yes. The No picture has a question mark because bad watershed conditions are only part of the consideration. The real question is whether those watershed conditions are leading to riparian degradation such as rapid channel aggradation, dehydration, greatly increased peak flows that are accelerating erosion.
- 03/22/10 The next big section of the attribute checklist deals with riparian vegetation
- 03/22/10 For riparian areas to continue to function, riparian plants must reproduce and occasionally expand into new areas. Recruitment is easiest to observe with woody plants that are young and obviously growing into larger plants. Recruitment can also be observed from new young herbaceous individuals such as new plants at the end of a rhizome extending into a bare area. Failure to recruit may be observed in an unbalance age class distribution or in plants that are so heavily grazed that they are unable to escape to become tall shrubs.
- 03/22/10 At least a couple of different species from each of the functional groups should be present where the potential exists for this. This usually includes a couple of different willows of other woodies, and a couple of different herbaceous stabilizers such as Nebraska sedge or a close relative. Monocultures, especially of exotic weeds signal a real vulnerability to instability from die off’s or an inability to handle the flow forces that are expected.
- 03/22/10 While many plants can use the moisture of capillary fringe zones above a water table, only water loving plants can handle the saturated conditions of certain parts of riparian areas. These are generally the plants that riparian areas need for bank stability etc. Bluegrass is a good example of a species often found in riparian areas that have become desiccated by channel incision. Whereas rushes and sedges typically have extensive root systems and they live in very wet conditions. The list of obligate wetland plants is beat reference for the group of plants this attribute refers to.
- 03/22/10 This terrace f bluegrass and dandelions is performing as poorly as expected. It just lacks the roos needed for bank stability.
- 03/22/10 Whereas these willow and cottonwood roots provide a strong defense against erosion even though the soil would be otherwise erodible with the fast water on this steep stream. Similarly the sedges growing next to this beaver pond (that blew out in a high runoff) are extremely effective at holding soil together.
- 03/22/10 This conceptual bar graph from the extensive work done by alma Winward points out the strong stabilizers as well as the streambanks that will not likely hold up.
- 03/22/10 A four inch cube of soil from a Nebraska sedge dominated community might easily have over a mile of roots and rhizomes. Soil cores from this type did not erode when put into the wall of a flume used to measure soil erosion. Generally the wetter plant communities had the stronger root systems.
- 03/22/10 In the left photo, there is a strong difference in vigor between the plants at the top of the drained meadow streambank and those that still have water where they have broken off. Sometimes vigor is highly visible as in the right photo. Other signals to look for include the width of Nebraska sedge leaves (as wide as your thumb is very vigorous). Insect galls or scale on willows can indicate a lack of vigor as can plants that are not growing well due to overuse. However, vigor is not the same as low levels of utilization. Plants that are grazed properly can be quite vigorous.
- 03/22/10 In questions 8 and 9 we discussed whether the wetland plants with the good root systems were present. Question 11 addresses whether there is enough of them to protect banks and to dissipate energy during high flows. Bare areas and areas with mostly the wrong kinds of vegetation are red flags.
- 03/22/10 What do you think about this stream and riparian area. It has cottonwood trees. Does it have enough of the right vegetation to protect banks and dissipate flood energy? Where are the willows?
- 03/22/10 Without the roughness to slow the fast flood waters, the bed material around the boulders simply washed away.
- 03/22/10 After the initial incision, continued erosion makes the channel bigger. This system will very likely require willows and new cottonwoods to recover its form and functions.
- 03/22/10 Obviously there is coarse woody debris here. That is not the question. Is the plant community here to continue to produce coarse woody debris. Many areas in Nevada have suffered the double whammy of beavers cutting the trees and then livestock management not allowing for new trees to replace the old. Elk in too great a number could do the same thing.
- 03/22/10 This community of woody plants continues to add woody debris and the rooted base of the tree willow also adds to the structure of the channel. Such woody plants are essential for functionality in many of our moderate gradient and steeper streams.
- 03/22/10 The last big section focuses on erosion and deposition.
- 03/22/10 Energy dissipation across a broad floodplain is often most important. Where valleys are somewhat narrow, rocks and coarse woody debris can also be important in the floodway. In the picture on the right, a road on the valley bottom captured the stream from the are where the woody riparian plants still remain. When the water found the straight smooth road surface during a flood, it accelerated and began to remove road material as it cut deeper and gained stream power by doing so.
- 03/22/10 Meandering channels are constantly on the move and they depend on vegetation for stability of their otherwise erodible soils. As meanders swing across and sweep down the valley, they leave behind point bars that must vegetate and stabilize to form the floodplain. Such area make a good barometer of current management needed for maintenance of functionality attributes.
- 03/22/10 Lateral movement of meandering streams is not the problem, although the rate of movement could be a concern if it is too fast. Are the point bars are keeping up to maintain channel width/depth ratios? However, some lateral stream movement is associated with excessive sediment deposition. This can result from beat out and over-wide channels that can no longer transport their sediment. Or it could signal an excessive sediment supply from upstream. Mid-channel bars are a common symptom of this.
- 03/22/10 Although the yes stream on the left has incised in the past, it has now expanded and recovered sufficiently to provide a new vegetated floodplain for dissipation of flood energy. The stream on the right dissipates energy across a floodplain in the upstream area but downstream, it has incised and floodplain waters concentrate their energy along with other stream floodwaters to continue incision and erosion.
- 03/22/10 The Yes stream on the left is narrow enough to transport sediment well. It maintains this width with riparian vegetation and floodplain access for energy dissipation. The No stream has such a large sediment supply from the instability of incision and the upstream headcutting that this wide area deposited a bar that is so high it entrenched the stream. The bar is too high for most floodwaters to flow across it and it will have to erode away to expose a new bar and floodplain for eventual stream recovery.
- 03/22/10 At this location where an interbasin diversion brings in water from another watershed, the stream receives too much water for the original stream capacity and rapid erosion has resulted.
- 03/22/10 The rating of PFC, FAR on NF is not based on the number of no’s or yes’s. Rather it is based on the definition. So, we have put the definition on the form for easy reference.