2 ponds with 6' height diference

[Meyer Jordan]

You would only have the amount of overflow from the top pond, maybe 1/2 inch. If you have some overflow of the lower pond would not be a disaster, or make the lower pond to withstand a 2 " increase in water if it is 1/4 the surface size of the upper pond.

This greatly depends on the size differential of the upper and lower ponds. Having a smaller lower pond could really be inviting problems especially if the lower pond has a skimmer.

 

[Ronfire]

Here are a few pictures of the area I will rebuild in the spring. The current pond with goldfish has no filter and doing ok.The plan is to have an upper pond that will be about 1/2 of the deck width then maybe a wide water sheet leaving the top pond dropping to a stream into the lower pond. If I use a wide water exit from the top pond it will reduce the amount of water that will enter the lower pond in the event of a power failure. Will have an overflow and auto fill in the lower pond. Might build a Skippy filter for the top pond with a low water fall into it and a skimmer in the lower pond. Pump and plumbing will be under the deck with the shortest runs and least elbows possible.Might have to go a little wider into the driveway area. Have lots of rocks available on the property to build with.

 

[Meyer Jordan]

If I use a wide water exit from the top pond it will reduce the amount of water that will enter the lower pond in the event of a power failure.

This will be true only if you do not increase the overall flow rate to compensate for the reduced waterfall effect caused by the wider weir.

 

[Jhn]

Since your concern was all the fish ending up in the bottom pond having two pumps would solve that issue.
I don't get much surface debris either but my skimmer still catches fish debris as well as any uneaten food. I haven't used bottom drains since my pond is liner. Don't know much about them. But even cutting out the skimmers and just having two waterfalls would solve your fish transfer issue

CJ, two pumps in that type of application wont work. One of the ponds would eventually get emptied, as the pumps would never exactly match each other in flow rate. The upper pond needs to flow using gravity into the lower pond.

 

[Stephen T.]

I have 2 ponds separated by 35' of small stream. All the fish in the upper pond 6'x9'x3' deep, kept moving down the stream, over the 18" waterfall and living happily in the lower pond 9'x12'x 42" deep. I used small rocks to make the outlet from the upper pond very shallow, then place a chunk of driftwood just above the water and rocks. Since then, no clogs and no fish migrating downstream! Without, the driftwood, they would just flop over the shallow spot and head downstream.

 

[Usman]

use barrier made of rocks stones to obstruct direct flow of fishes its very easy , make a buffer zone and fill it with different size of rocks and let it spill away as waterfall in a shallow wider flow , if in case fishes swim in still then u can add a wide mesh like fishing net or some thing too but i think fishes cant make it thru stone dam, fishes will swim down if there is straight smooth flow like canal

u can also add a skimmer that has outlet in lower pond?

if u have dry weather and less rain then keep the waterfall low in height or u will have problems evaporating and ur lower pond water level will go down pretty fast, upper will b full always

 

[sissy]

Even humid weather will suck water from your pond and so will wind .I know it has been extremely windy and humid here and have had to borrow water from my stock tank of water I keep handy

 

[Ronfire]

Water refill is not an issue, just cost some power for the well.
Was thinking about the bottom drain for the top pond.
Option 1- Could have it come out in the waterfall from the top pond at close to the same level as the top pond overflow, would be hard to guess the flow rate and would probably mulch the debris going down the falls to the lower pond.
Option 2- have it gravity feed into a top prefilter with a limited amount of draw down in case of plumbing or pump failure
Option 3- tie it into the intake side of the pump with regulating ball valves.as well as the skimmer and bottom drain from the lower pond with a check valve to stop the top pond from draining into the lower if the pump stops.
Option 4- is probably the best with 2 pumps 1 draws from the top pond bottom drain to filter back to the top pond and a second pump from the lower pond to a waterfall filter in the top pond. Rather not have the cost of 2 pumps for power and purchase but it would have the saftey of backup in case of a pump failure.