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    I am in the winter planning stage of a design project.
    I am in the middle of a 400ac agro crop field. the farmer is very good at modern farming technique. Fertilizers, plowing and herbicides are used in abundance. the field has topography that creates run-off right into a ‘ditch” that flows East to West in the middle of my property, I have 6ac.
    I want to capture and use this water for my project, but I am not keen on the fact that all of this water is bringing the chemicals with it. My question is:
    Can I build a structure to “clean/filter/scrub” this water before I let flow to the other desired uses on my property?
    An example would be to build a pond or swale that would allow the water to clean itself, pulling some of the pollutants out, before I turn it loose to do a good work elsewhere on the property. I would plant some type of “non-consumptive” product such as reeds or willow/poplar tree, to help with the cleaning of the water that comes. Thank you. Chuck






    Hi, Chuck.

    Your ditch flows east to west. How much change is there in elevation between where it enters your property and where it leaves? If you have more change in elevation, that makes it easier to design a system that relies on gravity to bring the water through some sort of filter or settling tank, through your field, and out to meet the ditch on the other side at the right elevation.

    My first instinct was that you should run it through a sand filter. That’s a general go-to for cleaning water, but on second thought, I don’t think sand filters can bring stuff out of solution. I think they just remove suspended particles, aka pieces of stuff. So if most of the contaminants are entering your property in the chunks of stuff, a sand filter would be a great solution; if they’re entering your property dissolved in the water, a sand filter would be a lovely placebo.

    See what you find by googling ‘bioremediation agricultural runoff.’ Might be you could do a sort of constructed wetland to filter sediment and uptake some of the bad stuff. Note that with bioremediation, some bad stuff can be digested or broken up by plants into constituent parts that are less harmful, and other bad stuff (like heavy metals) can’t be broken down. When you bioremediate stuff that can’t be broken down, the plants will remove the bad stuff from the water/soil and store it in their tissues. So if you have a constructed wetland, at some point you probably want to remove a bunch of biomass (and depending on how toxic it is, maybe send it to a clay capped landfill).

    It sounds like you might have a contentious relationship with your neighbor, but see if you can communicate with them enough to find out what stuff s/he puts on the fields. Knowing exactly what kind of stuff you’re dealing with might enable you to find the best strategy.



    Charcoal is an excellent filter, not sure of it’s durability for large amounts of chemicals but in co ordination with some other system …sand, water plants it could work well.



    Hey Chuck, I’m in a similar situation but not on that big of a scale. My neighbor likes using “round-up” instead of a weed whacker and his cousin (next door) is a pest control guy and I’m down hill from these guys. First thing is to check your well and use a water filter for drinking water, simple charcoal filters will do the trick and you can find cheap reverse osmosis filter setups on eBay. You can also find point of use charcoal filters that attach to your garden hose if you are worried (the “clean water fun” garden hose filter). As for larger filters check out the SONO filter used in Bangladesh to filter arsenic for some ideas. Of course the other thing is to look at the ditch and see what’s growing or not, look and see if any insects or reptiles are affected (2 headed frogs, etc.), take a soil sample from the ditch and get it checked, you may have a “free” fertilizer source; my neighbor’s run off is high in nitrates, I live in the woods and use wood chips as mulch/compost which needs nitrogen, so my neighbors runoff is go for that. My neighbor today told me he was going to spray for ticks because he wants to get chickens and doesn’t want them to get ticks, so I just mentioned that if he kills all the insects he will spend more money on feed; money always talks to these guys. Also if push comes to shove the EPA is on your side. Hope this helps some, good luck.



    I have been out of pocket for a few days. thanks for the replies.

    I guess I should be more clear with my question.
    KATHERINE, I am not sure at this time what the elevation change is, but it is a fair amount. The water really will move across as fast as it can go..
    My “Ditch” is where all of the water runs during a heavy water event such as spring thaw, heavy rains etc.
    the farmer uses todays farming methods and kills weeds and spreads fertilizers. I am not sure of the exact kinds but I don’t think they are anything out of the ordinary for such activity.
    We have no relationship as we have never spoke. He lives out of town and I have not been able to catch him when he is on the field, only when he is working and I don’t want to interrupt.

    As the ditch flows now, it will collect a lot of run off and move it across my property. Nothing stands for long. I have a lane that has a culvert and that will act as a dam to create a pond of sorts until it can all run through the tube. It might reach two feet deep at times like this, and it will flow over the lane of coarse. From the lane to the east property line is about 100’+/-
    I would like to make a legitimate pond and collect this water as well as the water that enters my land from the North/south ditch. It is much like the E/W ditch and they join right in the middle of my 6ac. This junction is where I would like to make a fish pond.

    I am thinking about developing a small pond/wetland/swale at the entry points to help “use” some of the Chemicals from the farm fields. Thinking about reeds, bamboo grasses or some other plant or structure that I will not harvest for eating.
    Maybe some fast growing trees for firewood/building material.
    I would release the water from this point of entry structure and then use it is a well thought out design before I release it to the big pond and finally off the property.
    I am really keen on keeping my pastures and the new design elements green this year. I want to keep the moisture in the ground rather than let it run off as fast as it can go.

    Does this make better sense?



    I was trying to post a picture but I cant figure out how to do it. Sorry for all of the edits



    Hi Chuck:

    Just a thought, I liked the comment about testing the water to determine what you are dealing with. It may be that calculating the pond size to sufficiently dilute the chemicals, adding plants to absorb some, may be sufficient for use on ornamentals and fruit trees. Perhaps a more extensive filtering system would be needed for vegetable garden watering (zone 1), or not, depending upon how far the water travels through your property or other filter arrangements used.



    Thank you Suzanne. The water would be collected right at the point of entry onto my property. During a heavy rain last week I had a “pond” that was over 100′ across and long. My desire would be to dig a real pond there and somehow clean or sanitize that water for use.



    Chapter 7.5 “Purification of Polluted Waters” (starting on page 172 of “A Designer’s Manual” by Bill Mollison) talks about strategies for filtering polluted waters using bio systems.

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