Riparian Restoration

Outline What’s a watershed? Willamette Basin Past Present Our Role Project Examples With this presentation we will explore the form and function of water and what our role is in its story. We will also discuss our role in watershed health and how we will help improve water quality and wildlife habitat this year as a class.

A watershed is an area that collects, stores, and releases water Collecting all water within the drainage area and channeling it into a common point. “A river is the report card for its watershed.” -Anonymous A watershed is like a funnel - colleting all water within the drainage area and channeling it into a stream, river, or lake. So on to the concept of watersheds. This is a diagram of a watershed. A watershed is defined as an area of land that drains to a common point such as a river, lake or stream. A watershed extends from ridge top to ridge top and includes all of the land and land uses within those borders. It is important for students to understand that a watershed is the land as well as the water and what we do to the land affects the whole watershed. In that way “a river is the report card for its watershed.” This diagram shows some common land uses within a watershed such as farming, housing and forestry. Smaller tributaries run into the larger river in this picture. Each of those small tributaries would have it’s own smaller watershed, so when discussing watersheds it is important to note scale. Often times the words basin or sub basin are used to talk about watersheds as well. Generally we are in the Columbia Basin and the Willamette Sub –basin, fro there we usually talk about watersheds such as the Tualatin watershed, one of the five Portland watersheds or some sort of that scale. A good visual is to have students put out their hands and cup their palms. The edges of their hands would be the ridge tops and you can have them think about what would happen if it rained on their hand (you could even use a spray bottle to demonstrate). Basically all the water would run down the lines of their hands (i.e. small tributaries) into a “lake” in the middle of their hand. The concept of a watershed is very important for the work that we do so make sure to hammer this one home and get a clear understanding for your students before you move on.

Watersheds in Oregon Here is a map of the sub-basins in the state. Explain the terms, watershed, basin, sub basin and catchment all mean watershed just on different scales. You can see how county lines and city boundaries (not on map) do not follow watershed divisions which often leads to conflicts over management and land use practices. Have students think about other manmade boundaries that might cause conflicts (state borders, country borders). Major watersheds in Oregon as defined in the 1997 Oregon Plan for Salmon and Watersheds.

THE WILLAMETTE BASIN Geologically active zone 12% of Oregon 70% of Oregon’s pop 4 million by 2050 Let’s look at the natural features of the basin. Oregon lies in a geologically active zone. As the ocean floor slipped beneath the continent, the Coast Range and Cascade Mountain Range resulted. The valley, or basin, between them is 180 miles long and 80 miles wide. Stretching from Cottage Grove to Portland, the Willamette Basin encompasses 12% of the state of Oregon. 70% of Oregon’s population lives in the Willamette Basin and a ton of people are moving here. Do Tracing watershed activity What are the qualities of Oregon that you enjoy and you think cause people to move here?

So, our charge is to figure out how to accommodate everyone without losing the qualities of the basin that draw people here in the first place. How do we make sure we have enough useable water for all living things in the basin? How do we accommodate all these people without losing the qualities of the Basin?

The Nature of Waterways Naturally dynamic Move sediment Floods Topple trees Form and reform habitats Dynamic Equilibrium Adapt to external change Looking at both the water and the riparian area of a stream- waterways are naturally dynamic. They flood, which move gravel, carve new banks, topple trees, deposit and redeposit sediment. New habitats are formed from all this movement- side channels are carved, other channels are blocked off with trees, protective areas for fish are created, spawning sites are cleansed while water is cooled. Also, floods enrich riparian areas for the important vegetation we just discussed. A waterway maintains dynamic equilibrium by adapting to external change to maintain its balance. If change imposed on a waterway is too fast or too drastic, it struggles to recover.

Example of a naturally meandering stream, with nearby urban pressure Example of a naturally meandering stream, with nearby urban pressure. Note the marshy environment, unconstrained banks, development limited. Marshy areas are important for urban runoff filtration and they act as a sponge mitigating flooding events. The floodplain has been left unmodified. Note the side channels which are great wildlife habitat, particularly juvenile salmon nurseries! If a waterway is channelized, we will discuss with environmental scientists the possibility of re-meandering. Undeveloped estuary- mouth of Willapa River in SW Washington

Healthy Riparian Corridors Supports Wildlife Can connect wildlife corridors Biodiversity Provides Shade Soil stabilization Toxin and sediment filtration from runoff Large Woody Debris Riparian Vegetation helps absorb energy during flood events. In the Portland metro area, 93% of wildlife uses riparian areas. The land and water connection is a very important one for both the terrestrial and aquatic environments and those that live in each. The land immediately connected to a stream or river is called the riparian zone. Riparian means “bank side”. Riparian zones are very important to the form and function of a body of water and the environment as a whole (and we are part of the environment, even in the most urban setting). They are transition zones between upland and aquatic zones. Vegetation in riparian zones provides shade for the creek. A shaded stream is a cool stream and cool streams are able to hole more dissolved oxygen (DO) for organisms (just as we breath oxygen on land, organisms breath oxygen that has been dissolved in water in aquatic areas). Riparian vegetation also allows for Large woody debris (LWD) input. LWD gives structure to a stream. It provides habitat for fish, helps absorb extra energy in a storm event, slows fast moving water, directs water up to a floodplain and aids in erosion control. Vegetation provides food for organisms both in water and on land. 80% of terrestrial wildlife in Oregon depend directly or indirectly on riparian vegetation whether it be for food or shelter or another need. Riparian areas act as filters for runoff that often carries excess sediment and pollution (sediment can clog up fish lungs, make it hard to see predators and prey and attract more heat to a channel which means low DO levels). They also help absorb water in a flood event and can store that water for slow release. The roots of riparian vegetation hold soil together on a bank so that erosion does not occur.

Healthy Riparian Corridors Natural riparian vegetation usually has deep roots. The deep root mass helps maintain the bank or shoreline structure by holding the soil together. This vegetation provides a barrier to the erosive power of the water. By reducing erosion, less sediment is transported to the water body. Reducing sediment helps keep fish spawning areas clear, reduces nutrients, and makes water treatment easier. B. Riparian vegetation can also help reduce the amount of sediment and nutrients that are transported in runoff. The vegetation physically traps sediment in surface flow, and uses the nutrients in the shallow sub-surface flow. C. Some riparian vegetation is a source of large woody debris. When floating or beached in a water body, debris provides shelter for fish and habitat for aquatic insects. In flowing water, the debris also traps sediment and helps create structure (pools, riffles and runs) in the stream. Pools, riffles and runs are important components of a stream's ability to maintain aquatic life. D. Riparian vegetation provides shade. Shade helps regulate stream temperatures by controlling the amount of sunlight that reaches the stream. Most fish species prefer the cooler temperature of shaded streams. Shady areas also provide refuge areas for fish. Less algae grows in shaded streams because reduced sunlight limits photosynthesis. E. Riparian vegetation is a source of small organic debris, which may include leaves, twigs and terrestrial insects. This debris is an important food source for many aquatic organisms. F. Riparian vegetation helps reduce stream velocity during high flow events. This helps to slow down the natural erosion of the stream bed. Rapid erosion of the stream bed results in a lowering of the local groundwater table. Once the groundwater table is lowered, it is very difficult for water-loving plants to re-establish.

Unhealthy Riparian Corridor G. An abundance of weeds and non-native plant species is caused by removal of the native vegetation. Often these plants do not have the deep binding root mass that the native plants had and streambanks become unstable and highly erodible. H. A lack of shade-providing trees promotes greater sunlight penetration, leading to warmer stream temperatures and a decreased capacity to hold dissolved oxygen. These factors can lead to an increase in algal growth and a decrease in the abundance of aquatic organisms. A lack of tree saplings is caused by over-grazing. These saplings are needed to replace the mature trees as they age. J. Large areas of bare ground are caused by trampling of the vegetation by cattle. Slumping and erosion of the bare ground increases sediments in the stream, lowering water quality. K. A lack of large woody debris limits available habitat for fish or other aquatic organisms. Note: Some healthy riparian areas (e.g. streams in grassland regions) may not have large woody plants and therefore would not contribute woody debris to the stream.

Healthy Unhealthy