Pond Boss Forums POND CONSTRUCTION Selecting a site Hill Country Ponds w/ waterfall & stream

1st post from a newly minted member and landscape contractor in Central Texas who is seeking pond design advice from this stunningly wise group of PondBossers. My experience is based on smaller lined ponds, water features, and a bit of research - particularly from this great site. Fortunately my customer for this project is a very patient friend who is really excited about it.

We are planning a series of 3 fish ponds originating from a draw, which seems to drain about 7 acres or so. We plan to augment the available water with a new well near the bottom pond. The dry creek bed has wonderful deep soil from silting over the years, but is surrounded by porous limestone (and lots of dry ponds) nearby. For that reason we’re thinking that we’ll line the ponds with 24 mil reinforced polyethylene covered with appropriate material (soil, gravel?) to protect from the deer, or ‘mice on roller skates’ as they are sometimes called here. Whatever cover we use, I’m hoping it will enable the clearest water possible.

The mid sized pond near thehouse is planned to be about 35x90 and we’re hoping to install large flat boulders at the waterline to form a ledge from which to fish and ponder. We’re planning for the liner to be tucked into the soil just above the height of the boulders, with the boulders sitting on top of the liner on an excavated earthen shelf wide enough to hold the boulders and deep enough that the waterline will cover the bottom of the boulders. Would love some feedback on this, particularly regarding the cushion needed for the liner, and methods/material needed to keep the liner cover material from sliding down the sloped sides of the pond.

The small pond will be about 75‘ downstream (-5’ ele), just in front of a culvert which extends under the main driveway. We’re hoping to pump water from this small pond back up into the house pond which will feed a waterfall and stream between the two, flowing at about 6500 GPH or so. At the moment we’re thinking that the water will flow directly back into the house pond, which will have the main spillway directed to the waterfall. Quite open to suggestions as I’m not sure what this will do to turbidity, water clarity, etc. Another possibility is that the return can feed a waterfall that drops into the pond – this would have much better visibility from the house.

Would it be feasible to have a 3 tier spillway for the house pond? Perhaps the first stage is spilling over the waterfall, then a siphon spillway maybe .5’ higher to contain the flow over the waterfall, and then an earthen aux spillway to handle the flood type flows. Thoughts?

The last pond , which is another 350’ down the draw (-10’ ele from house pond) is the biggest, about 3x the size of the house pond. This will need some work, as it is currently leaking badly, likely due to porous limestone. The plan is to locate the well near this pond, and pump water up to the house pond with the intent of keeping all of the ponds at a constant level. Not sure what kind of flow I’ll need, but the overflow will end up back in the main pond eventually, so it would seem that too much is better, as long as we don’t kill the electricity bill in the process. Was thinking that ~12gpm would be adequate, but would love your thoughts on this, appropriate pumps, etc.

I’m told that 220V is better for long runs (w/ pump connected sufficiently away from the water for safety reasons), so planning to drop a line roughly parallel to the draw from the house to the lower big pond. Although I’m not fond of the thought of digging 2 trenches (one for the 220 and 110 lines, and one for the irrigation pipe, control lines, LV lighting, etc), I’m thinking that this may be the way to go. Comments?

Above the house pond we’re installing a series of silt collection dams, the first of which basically ‘fans out’ the draw from 4’ to about 18’ and is roughly level laterally w/ ~2% slope ending with a leaky boulder damn. This in turn leads to a 2nd similar dam, with room for more silt before reaching the house pond. I’ve seen comments about using pits, fabric, plantings, etc., and would like your comments on best practices for silt collection. I’ve also seen what appears to be organic material rolled up in plastic mesh, forming long skinny flexible hose shaped cylinders (maybe 8-12” in dia) which are then placed in a U shape in road ditches to presumably catch silt and debris – would this be a good option for ponds?

For circulation in both the house pond and big pond, we’re looking at Bottom Diffuser-Type aerators. I’ve seen several comments that these should not be mounted at the bottom of the pond, but perhaps this is for colder water situations up north. Do these cause the water to be more cloudy?

For those who make it to the end of this post, I applaud your patience, and you have my gratitude. I’m looking forward to your insights.

Kevin

Welcome Kevin. I'll leave the liner stuff to those who have experience with it.

500 ft, if I'm understanding you, is a long way to run power lines. Have you considered a separate power pole for the bottom area?

Great input Dave, I'll dig into max runs for 220V runs. We have power available from a garage that is closer, but it will be tricky and involve a bit more work.

The thing that is nagging at me today is the ability to keep cover over the reinforced polyethylene on the sloped sides of the pond. There must be a material that can be made stable enough to avoid sliding down... then again, perhaps I'm worried for naught. I'll soon need to get this ordered.

Hey guys, just wondering if I may have posted incorrectly, of if y'all are just buried w work, which wd be a great thing! Looking forwrd to your help...

I'm really buried with work.

The rest of these guys are just goofing off.

Can any of you slackers help KDO?

KDO, not a lot of us have used liners so ignorance pretty well abounds here.

Mike Otto did an article for PB Mag about them a year or so ago.

cant spell ignrant so i plead dumb to this one. seems like it would take a couple of feet of material over the liner to not get saturated and slide. i know of a small goldfish pond where they used 1 to 2" creek bed gravel on a 4 to 1 slope that stayed in place. a refinery close had a liner that wouldnt stay in place very well so they put 2" gravel in bottom and on some pretty steep slopes and it stayed in place but they probably had 6" gravel on it. thats all i know.

Thanks Tim. Any more suggestions relating to the liner? A few feet may be quite cumbersome. Any liner experts out there? I'm wondering if gravel might not be a bad idea since I've read that Bass seem to prefer that for spawning (although this may be a small pond for Bass)

OK, maybe I should simplify this post, just too much to read in original.

1. Stocking Bass in 1/4 acre pond - is it feasible?
2. It appears that 1' min of freeboard is required above fully flowing Aux spillway - what is min elevation between Primary and Aux (Primary is 6" PVC siphon)?
3. Is a 6500 GPH Mag pump ok for running water falls into the pond?
4. Are falls a good idea, or would they cause too much turbidity? Mitigation possibilities?
5. Bottom profile: 8' max depth, ramping down to 3' - how steep should the transion be for 90' long pond (65' of bottom)?
6. Liner: to mitigate risks, we think liner is important. what is proper way to cover liner given 2:1 sideslope. Would gravel or clay mix be better to ensure that it doesn't slide down to bottom?

KDO I will try to help.

1. Stocking Bass in 1/4 acre pond - is it feasible?
Yes should be easy to manage.

2. It appears that 1' min of freeboard is required above fully flowing Aux spillway - what is min elevation between Primary and Aux (Primary is 6" PVC siphon)?

With only 7 acres of watershed I would design the primary to handle it all depending on the site and available space.


3. Is a 6500 GPH Mag pump ok for running water falls into the pond?
This video has a partial view of my water feature which is using a 3000 gph irriagtion pump.
As for size of pump it all depends how big and dramatic your looking to acheive. My pump will flow about a 1 to 2 inch deep stream about 20 inches wide.

4. Are falls a good idea, or would they cause too much turbidity? Mitigation possibilities?
Yes they can be used for aeration, Our leader Bob has written articles about this in the PB mag. He also talks about planting certain vegetation in the stream below or auxiliary pond to use as a natural filter.

5. Bottom profile: 8' max depth, ramping down to 3' - how steep should the transion be for 90' long pond (65' of bottom)?

With 3/1 slopes(the norm) a 90 ft long top elevation would make your bottom length approximately 57 ft long.

6. Liner: to mitigate risks, we think liner is important. what is proper way to cover liner given 2:1 sideslope. Would gravel or clay mix be better to ensure that it doesn't slide down to bottom?
I would contact these guys they are a PB sponsor. They are experts in the subject
http://www.coloradolining.com/gallery/gallery1.htm

Posting pics of the site would help the experts help you.
Good luck
Rocky.

Rockytopper, my hero! Thanks so much for the thoughtful response.

Primary/Aux spillway combination: Great idea, as it will save the additional height needed to accomodate both. Was hoping to also squeeze the freeboard a bit to maybe 8" or so. Do you think this is a big no no? If feasible, then maybe 4 siphons would handle the 25 year event (whatever combined capacity would handle ~4cf/sec), which would further reduce the height of the dam over the waterline. Any comments on this approach?

I like the idea of an aux pond prior to water dropping into the main pond - this sould reduce turbidity. Will see if I can find Bob's articles.

Do you know anyone that can make suggestions for the slope changes that Bass might like over the length of the bottom? What should the bottom terrain look like... perhaps not a straight line from 3' deep to 8'...? Maybe X' of 8' depth followed by a fairly quick ramp up to 3'... or?

Since we're dealing with such a small pond, was hoping we could push the limits of the slope to 2/1 if we can get the liner to hold its cover. Any concerns with this? I will also give Colorado Lining a call.

The slopes can certainly be achieved might have to use a track hoe. I'm sure a dozer could do it might just take a little longer to climb out with the load. I thank you said you only had 7 acres of watershed I believe or in vision you are going to create a waterfall and use a siphon to feed it is that correct? If so the top of the water fall is the emergency spillway just size the width to the max flow rate expected. There are a group of homes along a creek or draw near where I work. It is now a series of ponds one feeding the next all along it with homes sitting on 1 an 2 acre tracts. All the dams have a pipe or concrete spillway that handle normal runoff. However this stream has several hundred acres of water shed. In larger rain events many of the dams that do not have room for an emergency spillway around the end used large flat sand stone and concrete and basically cover the entire dam. That allows water to flow over the entire dam in a flood. Given that you have such a small watershed I assume you could consider this type of approach which would just integrate into your water fall stream landscaping plan if I understand what you are trying to achieve. You could run the liner completely over the dam which would help keep water from getting under it and cutting the dirt away. If it will help I will drive by on my way home and take a pic of what I am talking about and post it here. You could stair step the slopes of your pone and align with boulders partially and completely submerged for a natural hill country look. You have many options just depends on the projects budget. As for habitat the sky’s the limit. Many post on here and many different options. May be you should start a thread on show me your habitat designs and folks will join in . If not try searching in this section http://forums.pondboss.com/ubbthreads.php?ubb=postlist&Board=4&page=1
or perhaps one of the other PB regulars can assist in locating existing threads.

Hi Rockytopper, took your advice and started another thread on habitat - good call.

Regarding the falls, the latest thinking is that perhaps we'll pump water up the hill a bit and create a natural looking stream/waterfall that flows back into the pond to help with aeration, turn-over and aesthetics.

Combining primary and aux spillways per your suggestion could be enabled by several PVC siphons in parallel, enough to carry 4 cf/sec for the 25y storm event. I'd like to hear more about your stair steps on the side of the pond and how it may look.

Rainman suggested that I look at what AaronM did, since he has great production from an even smaller pond. Lots of good stuff there. You're probably already familiar with it, but he went with an Aquascape design with stepped down sides, liner, and a gravel covering for spawning beds - it appears that a primary benefit of the stepped down sides is that it will help to keep the cover material (gravel) in place.

Below the main pond we're looking at installing a smaller pond (puddle) for aesthetic purposes. It is kind of a silt basin now, so we thought we'd just excavate down a little bit and create a marsh/bog type thing. This almost sounds like the marsh/bog type filter that AaronM created for his pond, only his is placed before the pond, not after. RT, Do you think it feasible to pump the outlet of this puddle/marsh/bog to supply the waterfall so that we could take advantage of the filtering the marsh would provide before returning it to the pond? Of course this would involve a much higher "normal" flow rate in the stream leading from the pond to the marsh, as compared to pumping directly from the pond, but we could design the stream accordingly (typically the marsh would only get the overflow from the pond, probably less than 10 gpm or so).

KDO, I'm glad you found the info on Aaron's pond. I know you asked this of RT, but I'll address it also. Why not circulate your water though the bog and use the well/other pond to maintain full pool instead of a constant flushing? Seems this could decrease a lot of costs. A small bottom diffused aerator would be a huge help also to ensure a more complete filtration of the entire water volume.

Excellent idea Rainman. We're in synch on this. In our case the bog is after the main pond, so we're hoping to pump from the outlet of the bog to the the top of the stream/falls, and into pond from there. Good call on the diffuser as well. Did I read somewhere that these need to be moved around depending on the season? If I'm cycling 6500 gph through pond, would this be enough movement?

I think you'll be fine with that. The ammonia and nitrite is more toxic than the nitrates they are broken down into...the bog plants will take those up.....and algae. You would be surprised what you can do with specialized ecosystems in separate locations.

If I'm reading you correctly, In our case we have 3 systems... pond outlet/bog, pond, and stream/waterfall... Do you think we'll need the diffuser?