Phosphates from fertilizers, washed into the soil, washed into the lake...

[Raven]

blue/green algae blooms. Harmful to animals and children.

The above is about as much as I know about this. I am sure someone here knows much more. I have a project that I'm reviewing as Town Planner. It is for a landscaping/garden center to be located 50' from a brook that dumps into a major lake about 250' away. The lake has already had alerts from the State Environmental Department for these algae blooms and I'm told that phosphates in the fertilizers used at this landscaping operation will be a problem.

Will a biodetention area on the site prevent this problem? What happens to phosphates when they leach into the ground?

Any advice would be much appreciated.

[XemaSab]

1. Phosphates leached into the ground can travel, yes

A small pond that collects runoff from the site should suffice. Is that feasible?

[Raven]

2. Yes...some sort of a biodetention pond could be built. Over time,

what happens to the phosphates that are collected there? Do they ever go away or do they just accumulate?

Thanks so much for responding Xema!

[kristopher]

3. Point source pollution isn't really the problem...

Places like this can be controlled much easier than other, non-point sources.

What sort of vegetation is between the site and the water? If it is heavy brush or woods then it will be an effective filter. Perhaps you could condition approval on maintain a wider buffer zone. 50-100 feet is generally considered to be pretty effective.

How large is the facility and how much fertilizer would they use?
Over-fertilizing wastes money so most well run businesses tend to be not so much of a problem. Compare how you'd think a business would use fertilizer to how a homeowner would use it. Home lawn care is probably the biggest single source of nutrient runoff, followed by faulty/inadequate home septic systems, and then by farmers using animal wastes as fertilizers. They tend to over fertilize because they have to pay to dispose of the animal wastes otherwise.

It is fairly easy to calculate the amount of runoff that can be expected from the landscaping business and work out mitigation practices. Contact the EPA for help and science based solutions.

[Raven]

4. There is nothing between this operation and the brook and that

is why some sort of a detention pond is being considered. Good question about how much fertilizer is being used. I will try to find that out.

[kristopher]

5. It sounds like you should contact the EPA

or a local university. If you know how to approach the the analysis it is easy to determine if there is a problem or not, and if there is they can help calculate the most appropriate mitigation technique.

[MADem]

6. Maybe you can require that the center not use phosphate based fertilizers. nt

[XemaSab]

7. That would probably be close to impossible

On every box of fertilizer there are three numbers. The middle one is percent phosphorus. Virtually all fertilizers have some. Even organic fertilizers have it. :shrug:

[Dead_Parrot]

8. This might be a good start:

http://edis.ifas.ufl.edu/EP358

Seem to be a few options, and you'd probably want to get a specialist in to crunch the numbers for you. Constructed wetlands (which would be my preference, but only as a layman) are covered in a bit more depth here:

http://randd.defra.gov.uk/Document.aspx?Document=ES0132_3128_FRA.doc (word doc)

Good luck!

[Raven]

9. Thank you so much!