Hi all, I'm getting ready to rent the dozer and excavator. I'll be building a water table pond in an area where the table is pretty consistent with about a 36 inch range during really wet years. I've been reading a lot on the forum, its a great resource. If anyone here has experience in DIY water-table ponds, I'd love to get a conversation started about the don't-forget-to's and lessons learned. The soil here is VERY fine sandy loam, silty, and just enough clay to hold shape if you squeeze it real hard. I think at this point i'll be digging a "construction sump" and pumping the water out with one or two 3" trash pumps, with the intention of getting to 13' at the center. Total surface will be between .5 and .7 acre, fairly rectangular. Any advice on how to start the dig? I thought I might dig the sloped perimeter around 3 sides with the digger in the center, then start the shelves, working my way deeper and back toward the exit as I go. Any thoughts? I'm hoping you guys will ask me questions I don't know the answer too... -Muck
As I'm drawing out the design for this monster, I'm weighing the pro's and con's to having slopes between the depth shelves, or having stepped depth graduations. I know i want an area at 4' deep, an area at 8' and then an area a max depth, 12-15 feet. Because the soil is so sandy, should I expect the stepped walls to cave and become sloped anyway? I don't see a lot of info regarding slope outside of the shoreline portion of man-made BOWs. Are there guidelines that differ for what the intended use is? Soil types? species of stocked animals?
I've not built a pond of any kind myself, but I have done some excavating and have some food for thought...
1.) Digging a rectangular pond with shelves is easy in soils like you describe (no rock) so long as you start with the top shelf and the work your way down with out driving back over the upper shelves. This would risk a cave-in while your on the shelf. Scary.
2.) Expect the shelves to cave-in after the pond fills (or during) so make the shelves wide enough to account for that if you want some flats remaining.
3.) Will you be aerating the pond? I think a sloped bottom will circulate better with aeration compared to a shelved bottom.
4.) Will you be swimming in the pond? Shelves can be more dangerous, especially in loose soils due to cave-ins.
5.) Part of me likes the shelves concept, but then another part says why not cut the shelves out and make it sloped all the way around... This removes more of the soil in the same foot print and leaves less to slide back in and start filling in the bottom.
Not quite two cents, but it's free and welcome to the forums!
Thanks for the input. I had not considered the effect of the profile on possible aeration. I'll see if can find some info on those dynamics. I originally just wanted to dig a hole because I needed the dirt, now I'm a very interested in the pond as a whole. It is becoming a large part of the property development. I'm very excited. If anyone really wants to swim in the pond, I maybe will make a "beach" consisting of crushed rock covered with river rock and sand. I'm fairly certain the fam won't want to be in the mucky clay, so we'll see how that goes. I like the thought of removing more soil, but I've still got to calculate the final sq yds to (re)move and consider that when figuring the average depth. I may not need, or have a site for that much dirt. and don't want to truck any, really. Just like with anything else I do for the first time. The plan will probably go out the window as soon as i take out my first scoop.
I don't think the profile effects are a deal breaker either way, but just something to consider when weighing all the design pros and cons. The attached sketch simplifies the concept. The shelves will impede the overall flow to a small degree and the "nooks" (marked by the X's) will have less water movement. The smooth bottom profile will be more conducive to maximum and complete flow. Once again, not a critical factor. There may even be benefits to the nooks???
As far a beaches go...they rarely last two seasons before more labor and sand/gravel have to be added to keep them remotely fam friendly. Consider a dock with a ladder. A dock is so much better to swim from compared to the "muck in the toes". I know, pond ideas just keep coming, but if your family is as excited as you are about the pond...it will be a great place for everyone.
Nice drawing. I get it. I think that in practice the profile will not be so uniform that i should put a lot of worry into it. I'll be fighting the fill rate of the soil the whole dig, so I probably will have a lot of "good enough" after every bucket scoop. If i get to the point where i'm so good with the excavator that i'm within 6 inches of each scoop, i think i should celebrate. You're right about the dock being the way to go. That makes better sense. probably a floating dock. Thanks. It helps to talk it all out.
One of my experiences that you may run into is the amount of dirt that piles up in a hurry. I had bad dreams at night about what to do with it. We ended up blending it into the side of a hill and it looked pretty natural .
Weekend work: Got the cheap transit out, digging final test holes, and staking out the shoreline shape. getting ready for grading. Just a few weeks from bringing in the digger and dozer. Iím either going to feel like the king of earth, a kid in a sandbox , or one of those idiots on those old obstacle course shows that get knocked into the mud puddle... if itís not too embarrassing, Iíll chronicle with photos. If it is too embarrassing, Iíll be in my whisky chamber if anyone needs me.
Got a case 130 excavator and a case 750 dozer. I have some photos that Iíll compile in the end. Sucked about 150 lbs of sand into the trash pump lines today, holy moly that was a chore. Had to do some extra tree removal because the mud made me reroute my paths of dirt removal. Getting to the 12 ft depth is going to be nearly impossible. As the water come in from the table, it brings lots of sand with it, causing the banks to cave in and filling the hole with sand. It can be avoided by not going steep but Iím not sure it really matters... Advice for others: donít disturb the ground unless your going to finish in that area quickly, after it is ďuncompactedĒ it is much harder to move, wonít hold weight, and becomes super saturated very easily. I had a 50x20 ft waterbed this morning. It was ground that you could stand on, but waved like a bouncy house. Still on track. Lots of work to go.