How do I bring a contaminated pond back to life?

Not sure the best way to go about this.

I live right next to a pond that stretches  approximately an acre long, maybe 100 - 200 yards across where most wide, less than 5 yards at most narrow. It is covered in a blue green algae. It has eaten all the oxygen from the pond and killed all the aquatic life. I researched the pond and discovered it was once clear all the way to the bottom and full of fish. However, the owners of the property had horses. Years and years of dumping fresh manure directly in it has brought the nitrogen levels up way to high.

How would I go about trying to naturally bring the pond back to life? Or is it not really possible with a pond that big to get the blue green algae out and clear the water? I want very much to get the pond back to where it once was with fish and fresh, drinkable water. The current owners are elderly and cannot do any of the work required but have no problem letting me do it so long as I do not use chemicals to treat the water.

Any suggestions or advice?

Thank you a head of time.

If the algae is in mats, I would try to physically remove it. It will keep growing. I would remove that, too.

If this were a giant aquarium, I would make sure there was a pump and filter adequate to the job. For this situation, I would probably look into getting a solar or wind powered pump that has no problem passing large quantities of organic matter and water-borne sediment.

I would build something like a chinampas-style raised bed, with elements of sand filter to it, where the pond is shallowest and design it to accept the pump outflow. The water would be ejected by the pump and fall onto the bed (gently, you don't want it all washing away), where the water would percolate down through the soil and sand and then back into the pond, leaving algae and sediment behind.

If you had a more powerful pump and a sloped area by the shore where you could texture the land perpendicular to the shoreline, you could just blast the pond water up the incline a bit and have the textural elements (swales or deeper, narrow trenches filled with organic matter and backfilled) harvest the algae for you.

As long as you are regularly removing solids from the water, you will be improving the water quality. The pump, once the water is largely filtered, would do double-duty as an oxygenation device, should it be repositioned to shoot a plume upwards.

And if it's possible to ring the pond on-contour with sediment-harvesting features, you'll keep any horse manure from getting to the pond, unless it's deliberately dumped there.

Good luck, and keep us posted.

-CK

I think you can break down pond cleanup strategies into 4 categories:
Chemicals- which you said are out. And apparently when you do use something like copper sulfate, the sudden death of all the algae makes it own problems.
Dye- pond dye makes the water too dark for sunlight to reach the algae and it dies. Think mulch for a pond.
Digesters- pucks and liquids that help digest pond muck. Not really applicable to this type of algae.
Bubbles- get the water moving and aerated which gets rid of algae. These are either solar or AC powered.

I have a very small pond so running a bubble emitter on an air pump worked great for me. I worked with Practical Garden Ponds to find that solution and they were very kind in talking me through a strategy. info@practicalgardenponds.com

Solids removal by machine and aeration with bubbles or the sand / gravel filter will help a lot.
If manures have been dumped in, they will be close to the edges anyway.

Here is a link  to a site that will help.pros and cons of aeration
I got this from it.
"If you’re looking for decoration as well as aeration, an aerating fountain or surface dam aerator could be perfect for you, but if your aim is to keep running costs down, we suggest the installation of a sub-surface dam aeration system as moving air requires far less power than moving water. It may not seem like a big factor when you’re selecting your aerator but when you consider the fact that dam aerators are designed to run 24/7 365, those extra dollars on your bill quickly add up."

Maybe add some oxygenator plants. The below is an excerpt about starting a pond from scratch.

Submerged Plants. also called Oxygenators, grow with their roots anchored in soil, but the leaves stay underwater. Oxygenators are essential for keeping the pond healthy and the water clear. The best known examples include Anacharis (a deep green plant with many delicate leaves, which will grow in water 15cm to 150cm deep) and Hornwort (dark green grass-like leaves, need 15cm to 30cm of water above the crown).

These plants absorb carbon dioxide and release oxygen into the water, and by oxygenating the water they help it support more aquatic life such as fish and beneficial aquatic insects. They also absorb excess nutrients in the water and help purify it, which reduces the growth of algae. Oxygenators also provide food and shelter for fish. The leaves, which are usually fern-like, lacy, or hairy, provide cover for the microscopic aquatic life forms which are an essential part of a balanced aquatic ecosystem. From here.

It would be helpful to know the depth of this pond and what water sources supply it. Can you pump it down by 25% and have it recover with fresher water?

I agree with the posts above -- aeration is hugely important, along with controlling the quality of water coming in.

Regardless of the approach, this is no small undertaking. We're talking about a pretty large volume of water.

Have you asked your local county whether help and advice may be available?

Common problem. In a past job, I had to address this with several municipal agencies. The only real way to do this is labor intensive. Basically it amounts to nutrients and sunlight. Even in bodies of water where there are no livestock inputs, you see this problem on the nutrient side. Most water bodies get atmospheric deposition of nutrients...not just rain but at the air/water interface. Other inputs are runoff enrichment, diversion of drainage into ponds, etc. With all the nutrients all one needs is sunlight to complete the requirements for huge algal blooms. Algae grows like crazy and soaks up all the nutrients. As the algae grows, the bottom layers get less and less sunlight and starts to die off. Decay takes up all the oxygen and things die. The decaying algae, fish, etc also liberate the same nutrients back into the water. Without the removal of the growing algae, you are going to have a hard time interrupting the cycle. Without seeing more of your system, I can only make the normal suggestions. They will be the most effective but it will take a while and a lot of labor to right a wrong probably decades in the making.

Dyes are typically sold to reduce algal growth but all that does is kill algae and liberate the nutrients contained within the algal tissue. Also, that decay will further drop oxygen levels. You'll be adding dye forever and the underlying problems will persist. Dyes also affect non-target biota.

1) Fence off all livestock and direct drainage in livestock areas AWAY from the pond. You'll still get atmospheric deposition however.

2) Start removing as much algae as possible. Compost it somewhere away from drainage that would reach the pond. You'll need to do this in cycles...more frequently at first but over time you'll be able to tell when you need it. The idea is to let the algae take up a lot of nutrients and tie it up in tissue that is removable.

3) Since the pond is so narrow, you may have the ability for mechanical removal of sediments as well to help speed things up. However, disturbing sediments will also foul the pond for extended periods. Depth?

4) Look at the possibility of adding some shade. Given the narrowness of the pond, you may be able to address the light factor in addition to the nutrient side of things,

Once you've made headway with some of these measures, if you can pump out right before a few large storms, you may be able to help through dilution.

In sum, there are no quick fixes for decades of degradation. Keep chipping away at the problem.

All that said, I still live in one of the counties where I've given these same recommendations to agencies, parks, golf courses, and private landowners. Our main mats tend to be filamentous algae. These are fairly easy to rake although it is real work. Everyone looks for a magic bullet to make it all go away. They understand spray budgets and schedules and see no way to move away from that. The overwhelming majority of the places that had problems a couple of decades ago (and called me in for suggestions) still have them because they never moved from the comfort level of spray schedules and chemical budgets. Many also felt that the labor involved and the flexible calendar requirements were obstacles too large to overcome. However, the near-constant expenses of all of those years walking the spray and pray pathway have resulted in what? The issues are the same now as then. Only some of the decision-makers have changed and newer people are in those positions. The decisions are the same. "But we've always done it this way."

You can lead a horse to water...

It needs to find balance, I will assume that pumps and such are not wanted. Start pulling out the algae after a couple of goes you can probably add other plants, something that will shade the surface like duckweed or whatever floating plants you have in your area, then also keep pulling them out every time you pull out material you reduce the amount of nutrients in the water which will keep it clearer for longer, if you find after the algae mats are gone it goes green you can add daphnia (or other animal) Our pond would go from green to brown with daphnia and then the fish would get fat.

To get it totally in balance you'll need a mix of plants and animals and you can keep it balanced by removing some of both every year or every few years depending on the inputs.

"And if it's possible to ring the pond on-contour with sediment-harvesting features, you'll keep any horse manure from getting to the pond, unless it's deliberately dumped there."

How would I do this? And thank you for all the other advice. I figured it could be doable but was not clear on how. (also, I read about nitrate and algea eating bacteria I could put in the pond to help clean it out. Is this a good idea or would it lead to other problems?) Thanks again.

I agree with Skandi. I would focus on adding a diversity of fast growing plants that you put in immediately after mechanically removing the algae. They will remove nutrients and even toxins from water, as they grow. If the pond is large enough, some ducks and/or pigs can help you later on.

It gets to approximately seven (7) to nine (9) feet deep in some areas.

No, haven't asked the local county. The area is known for it's many swampy hollows. Often these swamps are "dammed" to create a pond rather than low lying wetland. The water table is pretty high here. Most properties have some collection of rain water gathering.

I will, however, look into local assistance to see if it is possible. I have a smaller (much smaller) pond on my property. It has plenty of plant life and frogs but not very deep or practical for much else than a frog pond. I will also be working on this body of water to make it as clean as possible. Except it has just been neglected and overgrown for many years and parts of the pond are choked out. No high nitrate levels in it. No horse manure.  But all these suggestion are going to help me with both! Thanks!

It sounds like your pond is in need of some fast growing native water plants which will be able to grow very fast to consume a lot of nitrogen while also providing functional value for wildlife.

Wetland plants (in fertile areas) tend to grow very fast so I am only making two suggestions which I have already confirmed to be native in Kentucky and so won't cause any issues with invasiveness.  

Nelumbo lutea is the native lotus with yellow flowers (not to be confused with the Asian lotus which may have white or pink flowers.  This is a large plant that will cover a lot of "ground" with lots of shade being produced by its umbrella of leaves which will help inhibit algae growth in addition to removing nutrients from the water.  A bonus is that this plant makes edible rhizomes as well as seeds both for humans and wildlife.

Sagittaria latifolia is known as katniss, wapato or arrowhead.  This plant will also grow and spread very fast in high nitrogen water and although its leaves aren't as large as lotus they have the remarkable habit of being very narrow in low nitrogen water and very wide in high nitrogen water.  Not only will they consume lots of nitrogen, but in higher nitrogen water their leaves will also provide more shade than in lower nitrogen water (algae needs the sunshine to grow).  Additionally, it will function as an indicator for how much progress is being made.  If you succeed in lowering the nitrogen levels you will see its leaf shape actively trending narrower on younger leaves.  Like the yellow flowered lotus, this plant also has an edible portion.  It makes starchy overwintering corms each fall which can be harvested (by stirring the mud so they float) and eaten as a vegetable.  It is also food for wildlife.   While this plant does grow anchored in the muddy pond bottom around the edges where the water isn't too deep, it can also be just thrown into the water without planting which will allow it to float around where the water is too deep for either it or the lotus to grow.  

To summarize, these two plants will both combat the algae in two ways; by significantly reducing the amount of sun which can reach the algae and by consuming its food source.  

Morning everyone!

Thanks to all the advice I received on this question. Here is an update.

First I am going to have to embarrass myself. Show my own stupidity. As I began working in the pond I noticed the "algae" was odd looking. Like tiny clovers. My stupidity was, it's NOT algae. it's duckweed, or watermeal as it is often called. Once I figured this out and that this plant hates moving water, I added a solar fountain and the continual movement cleared the pond up almost completely.
All these got the pond clean and clear to the bottom. A heck of a lot easier than I originally thought! The pond seems more, well until the cold weather, seemed more vibrant with a variety of plant and animal life.

Once again, I am embarrassed I got the content of the pond wrong, but an so thankful for all the advice!

Howdy,

Here is something that is on the local farm and garden listing. (Medford, Oregon Craigslist).

https://medford.craigslist.org/grq/d/phoenix-healthy-ponds-lakes-and/7416440804.html

Hello,

First bring in a pump to aerate the water,

Next bring in cattails and willows and poplars. to help with bio remediation. you cut these and take them away.

Later you introduce muscles. the living things!

this is little effort practice to clean up!

later the you remove the pump.

you can also reduce the run off of fertilisers with a subsoil bioreactor.

and fencing off and growing the trees is a great protective method!

Mike drop!

Regards,
Alex

I was about to suggest adding duck weed to absorb all the extra nutrients, but I guess it's already there. cattails are also good at absorbing extra nutrients. Both these plants are edible for humans and livestock. If you have a strong butterfly net you can pull out some duckweed easily. It's a great protein source for chickens or pigs. Cattails are a good carbohydrate for pigs or chickens too.

Willows or other water loving trees would be good to go around the banks too, they can throw a little shade over the water and lower the temperature which would make it more comfortable for fish.

Leora Laforge wrote:I was about to suggest adding duck weed to absorb all the extra nutrients, but I guess it's already there. cattails are also good at absorbing extra nutrients. Both these plants are edible for humans and livestock. If you have a strong butterfly net you can pull out some duckweed easily. It's a great protein source for chickens or pigs. Cattails are a good carbohydrate for pigs or chickens too.

Willows or other water loving trees would be good to go around the banks too, they can throw a little shade over the water and lower the temperature which would make it more comfortable for fish.

Ah the plants I listed where bioremediation plants.

to be pollarded, regularly, and moved on.

the algae is fed by the nitrogen fertilisers.

I listed the solutions to do so and to remove toxic and heavy metals, which could be turned to resources using natural systems proven by science and practice, by ecologists.

I figured this passive system could be easily undertaken by someone with elderly disposition.  my 97 year old grandmother could do it with a young guy for a afternoon ever other month.

I do not understand how a net could work on a pond of this size!

The problem is the solution?.  My understanding is the nutrient cycle is increased with the human activity so the aquatic plants grow quickly. It sounds like a great source of mulch and way to harvest the nutrients and place them back on the soil. Ive read the water hyacinth is growing like crazy in the East African lakes and causing eutrophication of the lakes (water stratification with layers of anoxic conditions). Why  don’t they drag the hyacinth up with nets and compost them to place the nutrients back on the crop lands? It seems a few fishermen could have part time work harvesting the water hyacinth grater than competing to catch the last few fish.
 I added duck weed to my ponds but didn’t let it get out of control. Add ducks do they eat it perhaps.