Actions producers can take in-between rain storms.
By Dr. Michael Payne and Denise Mullinax, CDQAP
Any producer who’s wrestled with local flooding, corral ponding and mud knows it’s easier to take preventative measures before the storms than it is to address them once they’ve begun. Every year CDQAP provides Tips for Water Board Inspections and every fall highlights Dairy Winterizing Checklists.
But what can be done after the rains have already started? Here are some things to think about while it is calm between storms.
Property Perimeter – Water Board staff advise that during and after storm events all dischargers (including non-dairy facilities) should check for threatened off-site discharge. Visually surveying the property perimeter provides final confirmation that manure infrastructure is working. This includes that tailwater berms are intact, pumps in settling basins and storage ponds are functioning, transfer pipes are not clogged and pathways for clean-water runoff have not been obstructed with debris.
Lagoons – Softened by prolonged rain and stressed by increased hydrostatic pressure, full earthen dams, levees and ponds can experience catastrophic failure. This is why dry-season prevention of weed roots and rodent holes is so important. During storm season producers should carefully monitor the integrity of lagoon and berm walls. Lagoon are required to have adequate freeboard (2’ for above ground ponds and 1’ for in ground ponds) to maintain structural integrity.
Lagoon water spilling over the top of containment walls can create erosion gullies, weakening wall structure. This “overtopping” phenomenon is also one of the most common cause of dam and levee failure and can progress rapidly to a crisis. Under no circumstances should a lagoon be allowed to spill over. If evidence of threatened overtopping, seepage or boils is present, producers should seek professional assistance immediately.
Levees –Producers whose property contains or is adjacent to a public or private levee may have obligations to maintain or at least not harm levee integrity. For both farm safety and legal reasons producers should monitor nearby levees and report threatened structures to county emergency management immediately.
Corrals –One way to minimize corral ponding is to prevent intrusion of clean rainwater into the lots. Some maintenance can be completed in between storms, such as unclogging and repairing gutters and ensuring their flow is directed away from corrals. Sloping, berms and drainage ditches can also help direct clean stormwater from un-manured areas from running into corrals.
Stormwater drainage from manured corrals to lagoon storage is essential. The Water Board requires standing water to be removed from corrals within 72 hours after a rain event. Furthermore, minimizing standing water and mud within corrals improves both animal health and milk production. Maintenance and repair of corral slopes can be difficult if not impossible during heavy storm periods. A period of dry weather, sun and wind might create a window of opportunity allowing for some re-filling, re-grading and compacting of corral surface. Manure & Feed Storage Areas – Both solid manure piles and feed storage areas should be protected from direct rainfall and run-on storm water. The methods described above for diversion of clean storm water away from corrals can also be used for solid manure storage and the feed area. Covering solid manure prevents rainwater from coming in contact with manure nutrients. This prevents manure run-off and Volatile Organic Compound (VOC) emissions.
Emergency Manure Management Plan – Accidents do happen and responding quickly can minimize recovery costs and legal problems. CDQAP has a template: Emergency Manure Management Plan. The Dairy General Order requires sampling any off-property discharge water, from crop fields, pasture, or the production area. Producers are referred to the CDQAP article: Storm Water Sampling: A Quick Review Just in Case!