Animal Lot Runoff Control at Wisconsin CAFOs

Transcription

1 Animal Lot Runoff Control at Wisconsin CAFOs Animal lots at a CAFO are reviewable under s. NR , Wis. Adm. Code. (Manure Transfer &/or Storage) A pasture isn t reviewable, but a pasture must be vegetated. (See definition of pasture in s. NR )

2 Minimum Design Criteria for Animal Lots 1) Liquid-tight containment, or an alternate design for a low permeability surface, to protect groundwater (gw) quality. 2) Collection of all runoff (up to the 25-yr, 24-hr storm) or an alternate design, to protect (gw) quality & meet zero discharge to navigable water. 3) Route clean storm water around / away from lot.

3 Animal Lot Surface Alternatives (other than liquid-tight containment) DEPENDING ON SITE CONDITIONS, THE FOLLOWING SURFACE MATERIALS MAY BE APPROVED: Non-liquid-tight concrete Asphalt Low permeability soil Combination of alternatives

4 Site Specific Conditions To Consider Soil type, depth to gw & bedrock. If bedrock is not deep, is the bedrock fractured or karst? Site susceptible to gw contamination? Lot size (all lots combined). Operation & maintenance. Stocking density, use frequency & scraping schedule? Is manure stacked on the lot? How well the lot surface is maintained? Other contaminant sources at the site. Existing gw quality in the area.

5 Animal Lot Runoff Control Alternatives (other than collecting of all runoff) DEPENDING ON SITE CONDITIONS, THE FOLLOWING RUNOFF CONTROLS MAY BE APPROVED: 1 st flush collection with solids removal, then route to a VTA. This may be approved, if total lot area is small (less than approximately acres) but no pollutant discharge to navigable water must be demonstrated. Refer to earlier slide for site conditions to consider. Also see the VTA presentation for alternative VTA designs to meet zero discharge to navigable water.

6 Calf Areas = Animal Lots CALVES HAVE ALWAYS BEEN INCLUDED IN THE NUMBER OF ANIMAL UNITS. HISTORICALLY, CALF AREAS/HUTCHES WERE NOT THOUGHT TO BE A WATER QUALITY CONCERN, DUE TO THE AMOUNT OF BEDDING USED & REGULAR CLEANING. HOWEVER, IN RECENT YEARS, RUNOFF SAMPLING HAS SHOWN SIGNIFICANT POLLUTANT DISCHARGES FROM CALF AREAS.

7 Hutches In a Variety of Settings

8 What Industry Experts Say Keep feeding area outside the hutch, so manure & urine do not build up in the bedded area. Keep calves healthy with proper hutch design and location Place hutches on a 1.5 feet thick layer of well drained stone. Be sure calf hutches always have enough bedding Article s in the Hoard s Dairyman

9 Good Drainage Below Bedding Is Recommended by Industry Experts It is critical to have good drainage, so urine, & spilled milk & water do not soak the bedding. A well drained surface below the bedding helps keep calves warm & dry, & minimizes flies. Below the stone/gravel layer, it is recommended to also install drain tile that outlets to a collection area outside of the calf hutch area or barn. Calf barns can equal hutches With the proper specifications, calves can thrive in a barn environment. Pen space is the number one factor whether calves are grouped or not. Ken Nordlund, D.V.M., Becky Brotzman, D.V.M. & Arturo Gomez, D.V.M. School of Veterinary Medicine, UW-Madison. Article in the Hoard s Dairyman

10 Bedding Types Recommended By Industry Experts Straw holds moisture & promotes flies. Fresh straw can be added over soiled bedding, but the moisture holding capacity & fermentation potential are increased. Sawdust or wood shavings will reduce flies. Wood-based bedding is less optimal for maggot growth due to less absorption of liquid & low availability of organic matter (organic matter is bound up in long, multi-layer lignin compounds). Other characteristics of wood may also be factors. Sand & gravel bedding will also reduce flies, but tend to get compacted & unsanitary after only a few weeks. The "ABCDEFGs" for healthy calves Neil Broadwater, University of Minnesota Extension Educator-Dairy

11 Inference Calf hutches & calf barn floors should be designed with drainage. Different bedding types have different liquid holding capacity. Bedding does soak up liquids, but has potential to release nutrients once saturation is reached. To reduce saturation potential, adequate drainage & bedding replacement is needed, so nutrients won t be released during rainfalls.

12 Are a Small Number of Calves a Conern? Maybe. Even an area with only a small number of calves can be a water quality concern. Evaluation of runoff control systems is discussed in a subsequent presentation.

13 Agricultural Performance Standards & Prohibitions in Ch. NR 151 Also Apply To CAFOs S. NR (4), WIS. ADM. CODE: a livestock operation shall have no direct runoff from a feedlot or stored manure into the waters of the state. S. NR (7) DEFINES DIRECT RUNOFF TO INCLUDE: Runoff from a feedlot that can be predicted to discharge a significant amount of pollutants to surface waters of the state or to a direct conduit to ground water. This includes runoff from calf areas at CAFOs & other livestock operations.

14 Is The Scrutiny Of Calf Areas A New Policy? NO. IT IS RELATIVELY NEW KNOWLEDGE THAT CALF AREAS ARE A WATER QUALITY CONCERN. POLICY REGARDING POLLUTANT DISCHARGES FROM A CAFO PRODUCTION AREA IS IN CH. NR 243 (& THE FEDERAL CLEAN WATER ACT) AND HAS NOT CHANGED.

15 Runoff Sampling U.S. EPA conducted site visits and collected water samples. This resulted in some livestock operations under 1000 AUs being required to get a WPDES permit. DNR did follow up with additional water sampling at CAFOs. Results of runoff control system discharge sampling are discussed in a subsequent presentation.