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After the Flood: Recovery Considerations for Rural Pennsylvanians

by Penn State Extension

After the Flood: Recovery Considerations for Rural Pennsylvanians

Parts of Pennsylvania were drenched with heavy rains and flooded streams recently. In addition to drying out wet basements, there are few important things that rural Pennsylvanian’s might want to pay special attention to.

Homeowners with private water wells and septic systems should inspect them for signs of possible flood damage, have repairs done if needed and consider a drinking water test for bacteria. Homeowners who suspect their drinking water was contaminated from floodwaters are encouraged by the Pennsylvania Department of Environmental Protection (DEP) to play it safe and boil all water used for drinking or cooking until their well is properly tested and disinfected, if needed.

Farmers growing corn should consider the impact of potential nitrogen losses some fields may have experienced due to excess soil moisture condition. Now is also the time to evaluate how your barnyard managed all the stormwater recently and, if needed, take steps to reduce damage and untreated runoff from future rains.

Inspecting Your Water Well After Flooding

After turning off the electric power to your well, inspect it for possible flood damage, especially if the appearance, smell, or taste of your drinking water changed following recent rains. Signs of well damage may include a cracked or shifted well casing; a missing or damaged well cap; erosion or mud deposits around the well casing, inside the well pit if your casing terminates below ground, or inside the well itself if the casing was topped by floodwaters. If your well only experienced minor erosion around the casing you may regrade and reseed the area by packing fresh soil around the pipe in the shape of a cone that will shed water away.  More significant damage like a shifted casing or sediment in the well, should be handled by a licensed well driller or professional pump installer. Flooded wells should be tested, and then if needed, disinfected. Instructions for well disinfection are available from the Pennsylvania DEP if you decide to do the job yourself,or you can hire a licensed well driller or plumber.

Drinking Water Testing

Having your drinking water tested will provide peace of mind that it’s safe to drink following a flood.  Penn State Extension recommends testing for coliform and E. coli bacteria  by a state accredited laboratory. Contact the Penn State Extension office in your county for more information on home drinking water testing available from Penn State.

Flooded Septic Tanks and Drain Fields

Flooded septic systems may not accept new household waste water or, even worse, cause backups inside your home. So, if your toilet or sink won’t drain, or your septic tank is draining backwards into your basement or upwards into your lawn, it’s time to stop using water in your house until the ground dries-out and you have a professional inspect both your septic tank and soil adsorption field. Don’t attempt pumping out the system yourself because water from saturated soil will likely fill it again quickly, may damage your septic tank, and could release dangerous sewer gases.

Heavy rains may have saturated your septic system’s soil adsorption fields which may slow, or even stop, wastewater treatment. If your soil adsorption field was covered by flood water but your household drains still work, and floodwaters have receded, minimal water use in the home is ok. You should wait until your drain field has dried out before gradually resuming normal water use and before you attempt any reseeding or filling of eroded areas or to remove flood debris from your soil absorption field. Attempting these repairs when the field is wet could cause damage from soil compaction. Contact your municipality’s sewage enforcement officer for additional advice and assistance on flooded septic systems.

Evaluating Nitrogen Losses in Corn After Heavy Rains

With the heavy rains we have experienced recently, it is important to access the nitrogen availability for your corn crop. Extension Soil Fertility Specialist Charlie White offers these thoughts. Generally speaking, excess moisture in the soil profile is one of the main causes of nitrogen (N) losses in crop production. These types of losses are due to either leaching or denitrification of the nitrate form of N. Leaching losses occur when water percolating through the soil profile carries nitrate below the rooting zone. Denitrification losses occur when anaerobic soil conditions cause microbes to convert nitrate to nitrous oxide or di-nitrogen gases which escape from the soil into the atmosphere.

For those producers trying to decide about whether to add more nitrogen to their corn crop, the answer will certainly be site and scenario specific.  Many indicators point towards N losses being rather limited during extreme precipitation events occurring in late July.  Areas within a field that will suffer the worst will probably be low lying areas where water ponds, causing denitrification.  Accessing fields with equipment that can apply additional N fertilizer into a 6′ tall corn crop also creates its own limitations. Since the areas within a field that need to be treated with additional N may be patchy, the economics of treating small areas with large equipment, or the economics of treating whole fields where much of the crop may not be responsive to additional N, may not be favorable. As always, understanding the processes that lead to N losses and integrating this understanding into adaptive management tactics will help you make a decision that best fits your individual scenario.

The extent to which N losses occur after extreme precipitation events in mid-summer, such as those occurring in July 2018, when there was 10 to 20 inches of rainfall across Pennsylvania within a 3-week period, depend on many factors. These factors include the timing of precipitation relative to crop N uptake patterns, the quantity of N in the soil profile in the nitrate form during the precipitation events, and soil drainage patterns.

Timing of Heavy Precipitation During the Growing Season

When extreme precipitation events occur later in the growing season, much of the N needed by a crop such as corn has already been taken up by the plant. For instance, corn in the silking stage (R1) has already taken up about 60% of the nitrogen it needs and corn in the blister stage (R2) has taken up 75% of the nitrogen that it needs.  The remaining N requirement of the crop may come from fertilizer that has been applied earlier in the season, or from N mineralized from organic sources, such as soil organic matter, cover crop residues, or manure applications.

Quantifying Nitrate-Nitrogen in the Soil at the Time of Heavy Precipitation

If a majority of the N fertility program for a corn crop is coming from inorganic fertilizer applications, it is likely that most of the fertilizer N applied has been converted to the nitrate form by the end of July. The exception to this is if a nitrification inhibitor was used with the fertilizer, which will provide about 6 weeks of protection against the conversion of N from ammonium to nitrate forms. The nitrate remaining in the soil profile is what will be susceptible to leaching and denitrification losses.  If a significant portion of the N fertility program for a corn crop is coming from the residual manure history, a previous legume crop, and current year manure applications, these organic sources of N will continue to mineralize through the summer. Mineralization of these organic N sources creates the ammonium form of N, which later in the season may be taken up directly by the crop before it is nitrified and susceptible to loss. Moist soil conditions in late summer may actually create more favorable conditions for mineralization, possibly increasing the amount of N available to the crop.  Therefore, the severity of N losses due to mid-summer extreme rainfall will be greater in systems where inorganic fertilizer is the primary N source for the crop as compared to systems where N mineralization from organic materials is a major source.

Soil Drainage Pattern Effect on Nitrogen Loss

Another factor affecting losses is soil drainage patterns. For leaching to occur, nitrate in the soil profile must be flushed below the rooting zone. This requires enough precipitation to recharge the soil profile with water to exceed field capacity, as well as enough precipitation to exceed the evapotranspiration removed by the corn crop. For a silt loam soil with a 24-inch rooting depth that has been previously dried out by a growing crop, it will take about 4 inches of rainfall for the soil to reach field capacity.  Any additional rainfall above that amount would then theoretically trigger an equal amount of leaching of water and nitrate from the bottom of the root zone. For nitrate that accumulates in the topsoil during the growing season, it could take several drainage events of this magnitude to push the nitrate below the root zone. Counteracting these drainage events is evapotranspiration, which is removal of water from the soil profile by evaporation and crop usage. A corn crop at full canopy on a sunny day will evapotranspire about one third inch of water each day.

Another aspect of soil drainage that will affect nitrogen losses is whether the soil remains saturated long enough for anaerobic conditions to occur and trigger denitrification.  Denitrification will occur when microbes use up oxygen in the soil. When a dry soil is wetted to saturation, it may initially take a couple of days for oxygen levels to be depleted to the point of denitrification occurring. If the soil was already wet to begin with, anaerobic conditions could occur even faster. These anaerobic soil conditions need to be paired with nitrate existing in the top soil where the microbes are most active for denitrification to occur. So, the severity of denitrification losses is to some extent tied back to how much nitrate is actually in the topsoil when the extreme summer precipitation occurs, which depends on crop uptake patterns and the predominant sources of N fertility in the system. Denitrification losses are also likely to be patchy within a field, corresponding to low lying spots with poor drainage where rainfall may accumulate and pond.

Preventing Barnyard Flooding in the Future

If you experienced flooding in the barnyard this summer, the best thing you can do is make changes now to prevent future flooding. The primary principal of managing excess water in barnyards is “keeping clean water clean”. The first step is to reduce the amount of clean water entering the barnyard. Proper spouting on the barn diverting all roof water away from the barnyard is a key first step. Another step is diverting runoff from upslope lands and other nearby rooftops. The less water that enters the yard, the less manure gets flushed off.

Another important step is to clean up polluted water that is leaving the barnyard. This involves trapping the manure solids and allowing the liquids to flow over a grassed area where remaining nutrients can be filtered out. Directing runoff to a manure pit is an excellent long-term approach when a liquid manure pit is close by.

Proper barnyard management will provide clean water benefits for everyone. But by keeping the barnyard and exercise area drier, there are numerous benefits that directly impact the farm operation. This will provide easier clean up and better use of the captured nutrients. There will be reduced clean up at milking time and less risk of hoof rot and mastitis and lower somatic cell counts. A better appearance on the farm will result in better public relations as well.