SU0004350 SSNL - Laserfiche WebLink

Home Browse Search

I CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL VALLEY REGION Fact Sheet leo. 5 For Dairies Soil And Groundwater Assessments IE'or Datries ~, F Introduction # The California Water Code requires that animal wastes be managed to protect water quality. To help achieve protection, regulations established pursuant to the Water Code (reference California Code of Regulations, Title 27, Subdivision 1, Chapter 7, Subchapter 2, Article 1, Section 22562d) require that holding ponds k utilized for animal wastes be lined with, or underlain by, soils which contain at least 10 percent clay and not more than 10 percent gravel or be lined with artificial materials of equivalent impermeability. In addition, Fthe Tulare Basin Water Quality Control Plan and some county ordinances require a 5-foot separation between the bottom of a holding pond and the highest anticipated groundwater elevation. i Title 27 also requires that manured areas (including corrals)be managed to minimize infiltration of water into underlying soils. Consequently, corrals and manure storage areas are usually designed and managed to reduce the potential for standing water ("ponding"). There are no state regulations that specify soil charac- teristics for corrals or manure storage areas. However, soils with low levels of clay and without underlying restrictive layers (such as a hardpan) are likely to allow significant infiltration. Studies conducted at dairies by the Central Valley Regional Water Quality Control Board have identified impacts to groundwater from r corrals and manure storage areas. The following information is-provided to assist dairy owners who want to obtain soil and groundwater z ' information related to environmental issues at existing or proposed dairy sites. Obtaining site-specific t information is useful in developing recommendations for dairy design and operation. The following are not requirements,but can serve as a guide for.discussions with consultants who conduct environmental assessments. Flo Assessments of Holding Pond Sites ' Clay and gravel content in the sides and bottom of holding ponds is best evaluated by collecting samples from the pond excavation. However, an initial evaluation of soils can be made by.„ising soil borings before the start of pond construction. The borings can also provide information on expected depth to groundwater. Cuttings or cores from the borings can be examined in the field by a geologist or soil scientist to assess soil type and soil variability at the site. If desired, soil samples from borings can be submitted for laboratory 1. analysis to evaluate clay content and/or nitrogen levels. Borings can be also be used to evaluate several potential pond locations and the site with the "best soils for a pond can be identified. Assessments of Corrals Soil borings in existing or proposed corrals can provide information on soil conditions including the presence of conditions that will restrict percolation. Analysis of soil samples from the borings can provide information on nitrogen levels under the corrals. Subsequent soil sampling and analysis can identify any changes in nitrogen levels to help assess the potential for corrals to impact groundwater. Fit