Using Information: Potentially Removing Spoil Piles
I was looking at some old photographs from 1955 that show Duck Creek CA after it was recently opened. Pool 1 is forested with boat lanes cutting linear strips through the timber to provide access to blind openings. You can also see Pool 3 and the tell-tale “X” shaped boat lanes to the BB and X blinds. These lanes have been great for access, but as I look at the information we have today (lidar data, which is a digital elevation model depicting the area's topography), they also provide some serious management complications. This week I was walking along these boat lanes to figure out how to minimize these effects and help water flow across the pool and off of the trees.
The spoil from the boat lanes was deposited adjacent to where it was dug during wetland development 60 years ago. Consideration of sheetflow and the surrounding topography was not taken into account when these lanes were cut half a century ago. The boat lanes act as water delivery systems or ditches and the spoil piles act as small levees. In the past few years we’ve notched several spoil piles to help the water on the back side of them drain. It would be ideal to remove them all. However, the dilemma is where to put the fill and how much would that cost. Filling in the boat lanes with the spoil is not an option, as it would prevent hunter access to the blind openings. Removing the fill and putting it elsewhere would require identifying a location that wouldn’t inhibit sheetflow. The only place that would appropriately qualify in and around a flooded impoundment is the levee.
As you’ve probably noticed, the road on the south and west sides of pools 2 and 3 are a little worse for wear since we had some vegetation removed last fall to set up the ditch work planned for this summer. We plan to clean the ditches and tidy up the roads later this summer. The road work provides an opportunity for us to remove some of the spoil within the pools and use it as fill. This will help us kill two birds with one stone. We will be able to help the trees by reducing the amount of trapped water within the pool, at the same time ensuring that traffic can be routed in and around Duck Creek.
So as I walked up and down the boat lanes I took notes, GPS points and photos to help me evaluate the various piles of dirt lining the boat lanes. Back in the office, I tied these observations to the digital elevation data. I was able to rank which spoil piles should have the highest priority to remove and which ones we could live with. Due to the partial maintenance of the boat lanes and adjacent spoil-blocking water drainage, the locations I identified had small diameter vegetation (blackberry, maple and willow) on the back side of the spoil or were clear. The image below is an example of a spoil profile that we can generate from the elevation data. The schematic shows that we can determine at a specific location how much dirt should be removed. This work will be incorporated into our summer plans and be finished by this fall.
The week is coming to a close, and I thought I’d show you all what we were up to and how we are using data to direct our renovation plans. Things have definately changed over the years, but the renovation work will help Duck Creek continue to be an important place for fish and wildlife use in the next 60 years.