UNDER CONSTRUCTIONKATHY I. MARTIN, PE
3122 Tall Oaks Circle Norman Oklahoma 73072
(405) 321-3176
September 16,1999
Re: Environmental Engineering Review of Proposed TeVelde Dairy
Summary Statement - Environmental Risk
...I have prepared a Summary Statement regarding the environmental risks associated with the proposed expansion of the TeVelde dairy from existing 100+ head dairy with dry manure system to a dairy with lagoon system. The environmental risks focus on the 600 head dairy Site itself with respect to the spring that feeds the East Branch of Verdigris Creek Class A cold water trout stream.
Summary Statement:
The hydrogeologic situation at the proposed dairy is as follows: The dairy is located approximately 1/2 mile northeast of the first spring that feeds the East Branch of Verdigris Creek. Topographic evidence shows that the groundwater probably flows from the farm to the west toward the spring. This spring fed creek then flows approximately one and a half miles before it is joined by other spring fed creeks. The total creek flow then traverses several miles of twisting paths to the fishery. The fishery is only three miles (straight path) from the dairy
Hydrogeologically, springs occur for the following reasons: (a) the groundwater originates in a semi-confined aquifer that contains enough reservoir pressure (potentiometric head) to cause the liquid to rise above the land surface or (2) the groundwater aquifer is unconfined and the erosion of the land surface has exposed certain portions of the aquifer allowing it to flow freely onto the land surface (water table). The first situation is usually associated with uplifted geologic formations which have recharge points exposed at the surface and the potentiometric head occurs at the lower portion of the slanted bed where the height of, the water in the formation causes the potentiometric head. An analogy would be a cask of water with the spigot on the bottom. The pressure of the water above the spigot causes the water to flow. The second scenario is more likely in the area of north central Nebraska in that this area contains the thickest saturated zone of the Ogallala Aquifer. The groundwater maps for that region show that the saturated thickness can reach as high as 600 feet and are known to create some areas of groundwater exposed at the surface, especially in low lying areas. In addition, the soil survey for Antelope County does not indicate any uplifted geology and is more representative of horizontal layers of wind deposited sands from the last ice age.
Assuming that the second hydrogeologic scenario were shown to apply to this case, then the hydrogeology is one of recharge over an unconfined aquifer system. The importance of recharge over an unconfined aquifer is two-fold. First of all, all precipitation that falls onto the land surface has the potential for infiltrating the sandy subsurface and "recharging" the groundwater. The second importance is that any seepage from lagoons would follow this same path from the land surface to the underlying groundwater aquifer. This means that any pollutants In the waste applied to the land during land application can be transported with the infiltrating precipitation (ie., rainfal and snowmelt) and any pollutants the wastewater that seeps through the lined lagoon will follow the same path.
It has been shown by the design engineer for the Dairy that the lagoon will be lined with "clays" that will be constructed to meet the state seepage restriction of less then or equal to 1/4 inch per day, which is equivalent to 6,788 gallons per acre day (simple mathematical conversion). Considering that the lagoon is designed to be 1.38 acres at maximum storage, the seepage is calculated to be 9,368 gallons per day and a potential for 3,429,403 gallons per year. Over a ten year design life, this facility lagoon will have the potential to contribute at least 34 million gallons of wastewater into the subsurface and ultimately the shallow groundwater located approximately 40 feet below the excavated bottom of the lagoon.
The types of pollution of most concern include total dissolved solids (salts ranging in concentrations of 3000 to 5000 ppm without recycle and upwards of 10,000 ppm with recycle), total nitrogen (concentrations of 500 to 1500 ppm depending on volatilization rates), phosphorus. heavy metals (including copper sulfate and other metals used as dietary supplements), enteric bacteria that may survive the rapid infiltration from the lagoon to the groundwater, biochemical oxygen demand (both from the manure and the milk parlor washdown), sanitizatlon chemicals, pesticides, and other conservative pollutants not known due to lack of wastewater analysis. Considering the concentration of salts, the amount of salts in the seepage water can be calculated as a range of 85,068 to 141,780 lbs TDS per year without recycle and up to 283,000 lbs TDS per year with recycle. The amount of nitrogen compounds can be roughly estimated as 14,176 to 42,534 lbs total nitrogen per year.
The applicant claims it will use in-situ clays to construct the lagoon but has not shown sufficient evidence that clays actually exist at the site, much less prove that the volume of clays is available to construct a one foot thick liner for a 1.38 acre lagoon. It is important to note that the above seepage calculations assume a perfectly constructed liner with seepage of 1/4 inch per day. If the lagoon liner is not constructed properly or constructed of appropriate materials, the seepage could be considerably higher Consider that the in-situ soils have a published seepage rate of 6 to 20 inches per hour or 2300 to 7680 inches per day. This is a serious problem not only if those materials are used for the liner, but also they indicate extremely rapid movement of wastewater that has "seeped" past the liner (as it is designed to do at a 1/4 inch per hour). in other words, once the wastewater has escaped the barrier of the liner then it Is free to move at speeds 1920 times faster than the liner seepage speed.
As I discussed with the personnel at the fish hatchery and as I informed the Supervisors, the wastewater will penetrate the groundwater aquifer and flow with it to its final destination, which is at this particular region, the spring that feeds the Verdigris. The types of pollutants of most concern are those that remain dissolved in the groundwater (i.e., total dissolved solids) including sodium, chloride, sulfates, and carbonates. These pollutants will significantly alter the water quality of the spring fed creek and cause irreversible harm to the aquatic habitat. In addition, it is possible that the corresponding biochemical oxygen demand will remain with the groundwater due to the chemical oxygen demand component and could reduce the dissolved oxygen content of the creek also causing severe harm to the cold water trout habitat (known for its sensitivity to changes in dissolved oxygen). Whether or not the BOD would be satisfied before it reached the fishery is unknown.
The wastewater treatment scenario at the proposed Dairy is as follows. The Dairy will be modified from a dry manure system that is currently used with approximately 100+ dairy cattle to a liquid manure system with 600 dairy cattle. The difference between a dry manure system and a liquid manure system is obvious. The manure is held in water and all pollutants that are water-soluble become dissolved in the water and are immediately mobile in the hydrogeologic setting. In a dry manure system, the pollutants are only mobile during a stormwater event.
The design or the lagoon precludes treatment. It was designed for storage only and is in fact 1/4 the size necessary for minimum anaerobic treatment and 1/8 the size necessary for odor control. If the lagoons were resized for treatment and odor Control, then the surface acreage of the lagoon would increase significantly. Since the seepage calculation is directly proportional to the surface area or the lagoon, the seepage volume would increase significantly as well, thereby compounding the groundwater contamination problem.
It is my professional opinion that this site was not chosen for environmental reasons, but for purely economic simplicity. The site and the size of the herd exceed many of the county zoning regulations, including setbacks from land used for land application of raw or partially digested liquids or slurries and the maximum loading of animals per acre. The location of the larger dairy that utilizes a liquid manure system is best suited in an area not associated with springs, cold water trout streams, or shallow groundwater. It should be built over subsurface materials that contain clays in thicknesses and vertical distances sufficient to protect the groundwater. It should be built with an above ground storage system so that leakage can be visually monitored. At no time should liquid manure systems be allowed to be constructed in the sandy areas of Nebraska using only a soil liner in an excavated lagoon. The risk to the groundwater and surface water is too high for such a low level of environmental protection.
The above statements were made by Kathy J Martin PE, of Martin Environmental Services with respect to the engineering and environmental aspects of the proposed Tevelde Dairy, Antelope County, Nebraska.
Date: Sept. 16, 1999
Prepared by Kathy J. Martin
Martin Environmental Services
Norman, OK
This is a transcription of the original engineer’s report. All errors and omissions are unintentional and are the responsibility of the webmaster.
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