RMZs and filter strips
Anna B Stockstad: Hi, everyone. I'm Anna Stocksad with University of Minnesota extension.
DavidNolle: and I'm. Dave Noly with the Minnesota logger education program.
Anna B Stockstad: Today we're back with another podcast episode, and today we'll be discussing the riparian management zone and filter strip guidelines.
Anna B Stockstad: Our guest today is David Wilson, who is the applied Science Coordinator with the Minnesota Forest Resources Council, and before that he was involved with the guideline monitoring program at the Dnr. So thanks so much for joining us today, David.
David C. Wilson (MFRC): Thanks for having me here.
DavidNolle: so i'll get it started off here, David, first off.
DavidNolle: No, I've been at this only about 18 months, and i'm i'm still confused, so i'm pretty sure there's a fair amount of confusion out there over the differences between preparing management zones. We call them Rmc's and filter strips. So
DavidNolle: how are these rms and filter strip guidelines different in what actually happens in application in the field?
David C. Wilson (MFRC): Yeah, good questions, Dave.
So we'll. I'll start off by just describing what riparian management zones are, and briefly, riparian areas are broad areas of land that transition from aquatic to terrestrial ecosystems, long lake streams and open water wetlands.
David C. Wilson (MFRC): They're characterized by an expansive set of forest resources, including plants, animals, habitat, and water that provide a lot of important ecological functions.
The Minnesota force, resource, council, force management guidelines to find a right pairing management zone is that portion of the riparian area adjacent to a stream, lake or open water wetland
David C. Wilson (MFRC): where right pairing management zone guidelines apply
Rm. Zs or areas that are dependent on the recommended Rm. Z width, and that varies according to the stream wake or open water. Wetland characteristics.
David C. Wilson (MFRC): Now a filter strip is a specific area of land adjacent to a water body that functions, trap sediments, experience and organic organics and pesticides.
David C. Wilson (MFRC): and another other contaminants from entering the surface. Water vegetation may include combinations of grasses, sedges, shrubs, and trees, or they can be dominated by one vegetation type.
Filter strips are identified prior to forest management activity, and they serve to protect any water feature type.
David C. Wilson (MFRC): The filter strip width is dependent on the water, feature, type, and slope. The minimum width is recommended to be 50 feet for all water, feature types. and the recommended with of a filter strip, as I mentioned, is dependent on the both the water feature, type and the slope
for slopes greater than 10. We want to increase the width of that filter strip by 2 feet. For each slow percentage above 10%
David C. Wilson (MFRC): forest management activities can be conducted within filter strips. As long as the integrity of the filter strip is maintained. Soil disturbance is the main issue here.
David C. Wilson (MFRC): And so we want to keep so with certain in the field to strip below 5% of the area and not concentrated in any one location, and that's really to help limit the the movement of that sediment into the water body. If disturbance exceeds 5, then the site must be rehabilitated to an adequate pre treatment condition.
We want to use slash, clean straw, or other appropriate materials to ensure that the filter strip will intercept sediment or nutrients from entering the surface water.
Anna B Stockstad: Thanks, David. I think that's a really good overview of the differences between arms. These and filter strips. I know it's really easy to get
Anna B Stockstad: confused, and I really think it boils down just to that difference in function. You know, arms. These are providing habitat along that transitional zone, and then filter strips are filtering out sediment. So I think Thank you for the really good
Anna B Stockstad: description of the 2, but I know it's also easy to get confused about where these guidelines do and do not apply. So, for example, what if you have a non open water. Welland.
Anna B Stockstad: Do the Rmc. And filter strip guidelines apply to those
David C. Wilson (MFRC): Yeah. Good question. So not open water wetlands. Don't typically require a riper in management. Zone Rm. Z. Guidelines apply on open water wetlands greater than one acre in size.
David C. Wilson (MFRC): A. And those require a 120 foot. Rm. Z.
David C. Wilson (MFRC): Open water wetlands less than an acre in size require a 50 foot Rm. Z. And all trout waters. Trout waters require a 165 foot. Rmz.
David C. Wilson (MFRC): But what I didn't mention is streams and rivers, and so streams less than 3 feet wide. Also get the 50 foot Rm. Z. And streams greater than 3 feet wide. Get a 120 foot R. And Z.
David C. Wilson (MFRC): So for these non-open water wetlands we would apply a filter strip
David C. Wilson (MFRC): we're talking about things like vernal pools. Seasonal ponds, mineral so wetlands, seasonal wetlands, seats, or springs. and then that filter strip with would be, as I talked about before, minimum of 50 feet, and then increasing with slopes greater than 10%.
Let's see, Rm. Z width is measured as slope distance. That's one important point, not the horizontal list. And so we want to actually kind of measure what the train is like on the out there on the ground.
David C. Wilson (MFRC): The the Rm. Z. With May, you know it may either be parallel to the edge of the water.
David C. Wilson (MFRC): following a a curved line, or it can be a straight line. But in either case
David C. Wilson (MFRC): we monitor that with, by taking through representative transects from the waters edge landward. and then determine compliance with the Mfrc. Recommendations based on the width of those 3 3 transects. So we average them
DavidNolle: right.
DavidNolle: So you know, a slightly different life. Not that long ago you worked in the guideline monitoring program before coming to your current position with Mfrc. So thinking back to then, you know.
DavidNolle: How are we actually doing with the implementation of Rmc's and filter strips, For that matter.
DavidNolle: maybe what are some things that you've observed? Or you did observe back, then, that that apply to Rm. Z. And filter strips.
David C. Wilson (MFRC): Yeah, good question, Dave.
David C. Wilson (MFRC): So with regards to repairing management Zones total implementation to to meet the force management guidelines has varied between about 56 and and 96 as of 2022 in the in the watershed sample unit monitoring that we do.
David C. Wilson (MFRC): Typically, it's been trending up and so overall the averages is a little over 70% implementation.
David C. Wilson (MFRC): but it it actually really is important to look at what is being done on the ground.
David C. Wilson (MFRC): So almost everybody is actually trying to do something regarding a a repairing management zone where it's recommended.
David C. Wilson (MFRC): And sometimes there are terrain, features or or site considerations that limit the potential width of the the right prairie management zone. And so in about 20% of cases we're seeing that slightly narrower Rmc's are managed
David C. Wilson (MFRC): and those typically average about 75% of the recommended, with. So so people really are working to manage these important right pairing corridors, both for sediment and and and hydrologic purposes and for the important wildlife habitat corridors that they represent
with regressive filter strips.
David C. Wilson (MFRC): Those are are
David C. Wilson (MFRC): almost always applied as intended. The only things that we're seeing are things like landings might encroach on on the recommended filter strip with.
David C. Wilson (MFRC): Sometimes a road might go through that filter strip or a skid trail could be established in there.
and those are are less than ideal conditions. Nonetheless, we really see
David C. Wilson (MFRC): excellent performance of these filter strips. They're they're somewhere around 99% effective in keeping that sediment and and nutrient load out of surface waters.
David C. Wilson (MFRC): So that's really good news, and and most people are pretty aware of what's going on. The the one caveat I would put out there is that it's really important to evaluate the site ahead of time during snow off condition, so we can really see where these
David C. Wilson (MFRC): wetlands are, and where that filter suit should be established, so that when we're out there during winter harvest, for example. we aren't, placing these infrastructure components within the filter strip.
Anna B Stockstad: Thanks, David. That's great to hear that monitoring is showing that implementation is pretty high for arms. These and filter strips, and it really shows that folks care you know about our water bodies here in Minnesota, the land of 10,000 Lakes. So that's great to hear.
Anna B Stockstad: And with that I just want to say thank you so much for being a guest on the podcast today. and to our listeners. Stay tuned for the next episode on wildlife and leave trees. Thank you so much for listening.
David C. Wilson (MFRC): Thank you. Anna and Dave.
