1 / 34

COMPLETEING A PRELIMAINRY ASSESSMENT FOR AG. WATER SUPPLY PONDS

COMPLETEING A PRELIMAINRY ASSESSMENT FOR AG. WATER SUPPLY PONDS. Water Quantity and Conservation #1. Use land according to its capability and treat it according to its needs Use management to gain the most agricultural benefit from precipitation and shallow groundwater

vanya
Download Presentation

COMPLETEING A PRELIMAINRY ASSESSMENT FOR AG. WATER SUPPLY PONDS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. COMPLETEING A PRELIMAINRY ASSESSMENT FOR AG. WATER SUPPLY PONDS

  2. Water Quantity and Conservation #1 Use land according to its capability and treat it according to its needs • Use management to gain the most agricultural benefit from precipitation and shallow groundwater • Improve water use efficiency • Keep runoff clean • Capture runoff and use it on the farm

  3. Farmers, Consultants and Partners #1 • NRCS wants the opportunity to assist you in development of a conservation plan that adds value to your land. • Why is NRCS ability to assist you with pond development limited to a preliminary site assessment? • Time- people w/ pond experience, broader mission • Money- program funds targeted, demand v. supply • Red tape- the federal compliance burden

  4. Farmers, Consultants and Partners #2 • This process is for ag. water supply ponds- irrigation, stock watering, wash water and cooling water. • Do you need to use this process? • NRCS workload priorities might be directed elsewhere when you request assistance. “ I won’t be able to assist you right now, but I’d like to get some information about your needs and if time becomes available we’ll get in contact with you.”

  5. NRCS and District folks- #1 • Are we getting back into the pond business? • Is this the only training I’m going to get? • Please don’t over-think this assessment • Off-site evaluation • No lay-out • No design

  6. NRCS and District folks- #2 • Use pond interest to engage in on-farm planning. “Can I get you to go on site to look at my place?” • Prelim. Site Assessment “pre-planning service” • evaluate candidate site’s natural resources for capability of land to support pond development • explain potential regulatory issues • enable early identification of problems with a proposed site that can be changed or solved because the idea is still being developed • help farmer’s develop ponds they need • will save farmer’s time in the overall process by ensuring practical alternatives, site limitations and regulatory issues are considered before large investments of time or money are made

  7. Rules of Thumb #1 Not all sites are good candidates: • Soils and geology can cause limitations • Size of drainage area • Flood hazards • Unique cultural or environmental features Ratio of drainage area to pond surface area affects water level • At least 10:1. Not more than 30:1. Mid-range is ideal. Good soil conservation in the drainage area is important

  8. Rules of Thumb #2 Irrigation storage: • at least 1.3 to 1.5 acre-feet of storage per acre irrigated Evaporation and seepage losses: • 2.5 to 4 ft. per irrigation season Beef cattle require at least 15-20 gallons per animal per day. • Pond may not be best alternative for livestock water supply. NRCS has published technical references that can be used to support planning and design: • National Eng. Handbook, Ponds and Reservoirs • NC Irrigation Guide • Conservation Practice Standard: Pond (378)

  9. Use ArcMapNavigate toArea of Potential Pond Site

  10. Define Area of Interest

  11. Bare Earth Data Converted to Tin

  12. Tin Converted to 5ft Contours

  13. Site Characteristics Question 1: Estimated Drainage Area

  14. ASSUMPTION: For THIS Example - 10:1 Ratio of Drainage Area to Surface Area of Pond NeededIDEAL = 20:1 Ratio

  15. 68 Acre Drainage Area=6.8 Acre Pond

  16. Site Characteristics Question 2: Estimated Pool Area

  17. 931’ 955’ Site Characteristics Question 3: Estimated Depth of Water Elevation Difference - Lowest Point to Top of Pool Area

  18. 931’ 960’ Site Characteristics Question 4: Estimated Embankment Height Add 5ft to Embnakment Height for Freeboard and Spillway

  19. Site Characteristics Question 5: Estimated Length of Dam

  20. Look Downstream • What Hazards are Observed? • Measure the Distance to Any • Downstream Hazards • Create .pdfs to Attach to • Assessment Showing Potential • Hazards

  21. Following General Guidelines Referenced in USDA: Ponds – Planning, Design, and Construction

  22. Based on Embankment Height of 29ft = Dam Width of 14ft Assume 3:1 – Outside Toe Assume 3:1 – Inside Toe 94 ft 94 ft Estimated 188 ft of the Stream Filled by Embankment

  23. Using Soil Data Viewer ArcMap or Toolkit Environment

  24. Use the NC Floodplain Mapping Program Stream Data to Determine if a Blue Line Stream Exists

  25. Calculate Feet of Stream Inundated by Pond Length of NCFPMP Stream Inside Pond MINUS Length of Inside Toe 631 ft – 94 ft= 537 ft

  26. Does the potential pond area fall within the boundaries of the property owned by the person?

More Related