Integrated Water Harvesting Earthworks, Restoring Ecosystems with Permaculture Design

[Applause] when i was eight years old i experienced my first major ecological catastrophe the spot that i hung out in as a kid with my friends was graded down to dirt terraced and paved over to be turned into a housing development by excavators the whole landscape had completely changed and i went home in a fit of rage i tore the poster that was on my wall it was simcity it was this poster that showed this nintendo game where you build cities i ripped it off of the wall and i left up the poster of rampage which is was this game where you play the role of godzilla or king kong and you destroy cities i left it left it up and i i vowed as an eight-year-old to fight development yet here i am sitting in one of those machines and i think it's because i believe that right now we have to leverage all the energy and resources we can towards the regeneration of the planet and the restoration of landscapes in our area rainfall has decreased by about 50 percent in recent years and at the same time rainfall intensity has increased by about 200 percent one of the effects of decreased rainfall and increased storm intensity is that when the rain does fall it doesn't necessarily penetrate into the heavy clay soils that are prevalent in this area and it can actually sheet across the land and run off without actually percolating deep into the soil and nurturing the roots of the trees these climate-driven factors overlap with land-use practices that by design or consequence have led to the rapid movement of water out of watersheds so this includes modern plantation forestry roads diversions that includes historic practices like the trapping of the beaver water diversions for mining and log drives all of these practices have compounded on each other to lead to a situation where water is extremely in deficit in the landscape when i arrived in this valley 15 years ago the creek would be dry by about mid-july old-timers remember the creek flowing year-round and over the last couple years after most of the upland forest in this basin was logged the creek is dry by about the first of june we're seeing the trees die we're seeing the creeks dry and we're watching climate change occur in real time [Music] upstream of this land is pretty much private timberland and that land is managed as a clear-cut based monoculture douglas fir plantation and that's the style of forest management practices that are mostly found throughout western oregon and elsewhere and there's actually research coming out of various universities in oregon and elsewhere that's showing a direct correlation between reduced stream flows and clear-cut based forestry practices that style of forestry is based on coming in and cutting the harvestable timber and leaving an exposed landscape which is hotter and drier than surrounding shaded forest areas another factor that recent research has found is that those rapidly growing trees after a certain time period actually increase the amount of evapotranspiration that's the water that the trees are taking up out of the soil and releasing into the atmosphere as they're between 20 and 40 years old that evapotranspiration rate really increases rapidly compared to older trees so when we have this plantation style forestry where the trees are actually harvested around 40 years of age we're seeing that there's actually more water leaving the landscape during that active growth period of those trees than if those trees were left to grow longer and older so that's one of the factors that we feel like is contributing to reduced stream flows in our area and one of the reasons that we felt really strongly about placing this pond and other earthworks here on the property with the hope being that eventually we could help augment those stream flows and keep water around in the landscape longer [Music] earthworks are one way that we can reverse this loss of water from watersheds through soils capacity to wick and hold immense amounts of water as well as ponds ability to retain that water longer and pressurize the water so that it sinks into deeper soil layers we get a widening of the lens of water in the soil and an increased ability for that water to do beneficial work in the landscape the lens created by a pond increases plant growth and through that increases carbon capture increased water availability leads to more water for wildlife it leads to springs re-emerging and ultimately at the landscape scale builds on itself to increase the base flow of streams and can return them to year-round flow this pond was done as an education project in order to empower people to understand how when and why to build these ponds first we'll remove all the tops of all the organic soil set aside and we'll get down to the subsoil everybody really has the ability to do this one can place logs and branches as check dams by hand and that type of work can restore the floodplain reconnect the waterways to the historic floodplain channels and return a creek to europe flow without even bringing in a big machine siding a pond is certainly one of the most important aspects of a pond project what you're wanting to look for is the location of the pond in relationship to what it's irrigating what it's supplying you're wanting to locate it as high as possible in the landscape while also situating it so that it can catch as much water as possible from upland sources i think you need to go up like because you're under the bubble you're almost placing the pond at the highest low point technically speaking that's considered the key point the key point is the place where the land goes from being steep to flat when you look at it from a topographic map what you see is that all the water flows perpendicular to contour and concentrates in this point so we've identified the key point we've also found through digging test pits that the soil is adequate for holding water we dug a pit in august and that pit filled up with water in three days that was a very dry time of year here in oregon but also digging as deep as we could go with a bucket and then cutting out a slope that was safe so that nothing could get stuck in it we saw that the soil type was adequate for building a pond [Music] ideally what you have is a porous surface layer that transitions into a highly impermeable subsurface layer that can create a permanent seal on your water and water will percolate in and run on that what this reveals is really i mean just an ideal situation this would be the a horizon of the soil and this is a dark silty clay loam it's gonna have a little bit more s more um sand and organic material in it and then below that it kind of transitions into this lighter salty clay loam to almost pure clay i mean this is like ceramic and then this horizon transitions into this more kind of like rocky clay which is essentially a mix of clay and fractured bedrock and then it gets to pure bedrock and i'm standing you can see that there's a little bit of flow and that's running right on the surface of the bedrock here so what what we're primarily going to want to work with is this clay material and this is going to form the interior core of our dam and it's also going to be used to create a seal along the dam and the um the bottom of the pond so that as water emanates in from from upslope and and out of uh porous layers it'll encounter this and just have a complete seal so the next step was preparing the site we surveyed where the ultimate water level would be where we suspected the dam height would be and what the width of the pond would be should really invent a laser level that instead of beeping like that makes bird calls or something and also we surveyed the plants that were existing within the footprint of the pond so making sure that we weren't going to be impacting any rare threatened species there's this nice monkey flower in here that i'd really like to dig up we cleared the shrubs in the brush [Music] the next step was deciding which trees specifically we were going to take out so it's definitely got beetle pressure in it i mean you can see in the cambium how much the yeah it's totally starting to griddle it already but you know this is probably an 80 year old tree if it's under attack already leaning into the pond into the pond in 25 years like you don't want anything that's gonna threaten the damn wall that could breach it or something like that [Music] [Applause] that top is really leaning out isn't it we must just have a couple of branches hung up yeah we don't want to leave that very long wow all right we're still up there easy peasy yeah we staged them for on-site milling and processing and the next step after that was to clear the topsoil so this topsoil special and at the end of the project we drive back across the dam and we scoop the topsoil back up and spread it over the top of the dam and what that does then is it creates a good substrate for new grass and other herbaceous vegetation to establish on top of the dam we spread it around the back side of the pond as well the next step is to trench out the area where the key goes so the key is a cut trench in the middle of the location of the dam you dig that out down below the excavation pit level and we began to construct our dam by placing a wall of extremely high clay content soil into the center of the dam we build that key up until we get above the elevation of water level here we have the benefit of having a lot of clay content and it's said that if you have more than 40 clay you can build an earthen dam that holds and also retains water and i built this up until i was above the ultimate water height by about three feet the dam over time will settle a bit i'm anticipating that probably the dam will come down to about two feet above the water height at about every foot of added soil to the dam we track rolled the dam with the excavator a number of times in order to compact it as well as possible this dam was built so that it was wide enough to be able to accommodate vehicle traffic over it from the key line road but all dams don't necessarily have to be this wide what i did then is i cut a spillway through one side that would set the ultimate water height below the ultimate height of the dam the spillway is built to be able to handle three times at least the maximum anticipated water flow coming through the channel and into the side of the dam near the spillway we placed a trickle tube it is set just below the height of the spillway and it takes the subtle flow during the non-rainy season and diverts it to a pipe which runs out and around the side of the dam so that the earth and spillway doesn't take a small flow of water year round because that flow can slowly cut away at the spillway it might seem a little technical but it's not very glamorous you really just scoop in place and scoop in place for days until it's done [Laughter] a lot of dirt [Music] once the pond was complete it took about four or five months to fill completely and we were coming up here every few days to check on its progress as it moved inch by inch with every passing rainstorm over the years we've dug a series of ponds and other earthworks on the property which have served to help harvest and maintain the water on the site throughout the year this pond here is kind of the capstone of that earthworks project and it serves to feed into all of the ponds lower on the property when we began this particular valley would have very little water moving through it watching these ponds i'm seeing that they are rehydrating the landscape i'm seeing the water flowing over land longer into the dry season when i'm walking in the woods i'm seeing that the vegetation is green downhill of the ponds and we're not needing to irrigate our orchards and our forest gardens so this type of water harvesting earthwork is one that does retain water but slowly releases it through the soil to the surrounding environment and so we have both a balance of meeting human needs and providing benefit to the ecology too often the focus in pond development and pond permitting is this idea in regards to human use that it's a degenerative force and too often it is but there's a right way to do something that can lead to beneficial socioeconomic outcomes at the same time are assistive and regenerative to the environment and also us who are part of it [Music] it's my hope in demonstrating this work that we can further the idea that developing these ponds is something that should be encouraged and promoted by local divisions of government and regulatory agencies one of the reasons we are really excited about this pond is that we feel like it's a really good example for local landowners and land stewards to potentially replicate on their sites as a means to enhance biodiversity and overall watershed health i think about what this could look like at the watershed scale this is a 40 acre property in the midst of a 400 acre watershed basin we could do this work on every tributary within this basin there's at least ten so we could have easily 100 of these ponds scattered throughout this basin contributing water to the stream channel you could only imagine what this would do for wildlife and for the biological potential of the forests in this watershed particularly if you coupled this with other practices like placing check dams in the in-sized channels to return the flow to its easily 100 foot wide flood plain or if you were to increase the width and the diversity of the stream side for us not to mention returning forests to mixed species mixed age stands i'm sure that we could see a return of the creek to year-round flow this is just a tributary creek of a sub-watershed of a sub-watershed of the willamette valley you can really imagine how all of these minor tributaries contributing to the land valley itself this work can rapidly restore the hydrology of watersheds [Music] [Music] [Music] you

Channel: Permaculture Institute of North America

Views: 150,107

Rating: 4.9196477 out of 5

Keywords: Permaculture, water harvesting, pond building, keyline pond

Id: wV4iSy4tTXc

Length: 19min 17sec (1157 seconds)

Published: Mon Nov 02 2020

Reddit Comments

[u/strangehitman22]

Neat!