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Bren 4 understanding surface water runoff


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Bren 4 understanding surface water runoff

  1. 1. Understanding Nutrient & Sediment Loss at Breneman Farms - 4<br />Understanding Surface Water Runoff at Breneman Farms <br />Kevan Klingberg, Dennis Frame and Fred Madison<br />UW Extension/Discovery Farms<br />Anita Thompson, Amanda Crowe and Tim Radatz<br />UW Madison Biological Systems Engineering<br />
  2. 2. Breneman Farms<br />On-farm research was conducted on the Breneman farm to investigate environmental challenges and opportunities for grass-based dairies on the Wisconsin landscape, 2002-2007.<br />Surface water quality monitoring was conducted to measure sediment and nutrient loads in runoff water from paddocks that were used for regular rotational grazing, then again used to seasonally out-winter the dairy herd.<br />
  3. 3. Breneman Farms<br />Grazing-based dairy.<br />42 paddocks.<br />80 crossbred dairy cows + young stock. (1.6 acres / AU)<br />Coarse textured soil<br />Out-winter cows and older heifers<br />Columbia County, WI <br />
  4. 4. Breneman Farms<br />Total watershed = 142.7 acres<br />Area east of road as well as western wooded area were determined to contribute negligible runoff towards watershed outlet.<br />Monitored acreage adjusted to 28.5 acres.<br />Monitored area: small watershed where cattle are grazed through the season as well as out-wintered. (middle area)<br />
  5. 5. Data<br />The data presented in this presentation were provided by the UW – Madison Biological Systems Engineering Department, as part of a cooperative project with the UW-Discovery Farms Program.<br />
  6. 6. Data<br />Breneman Farms, Rio, WI: Monitored surface water runoff from October 2005 – September 2007.<br />Field year = 12-months (Oct 1 – Sept 30)<br />Always represents the year in which it ends<br />Field year coincides with the crop year. <br />
  7. 7. 2006 Field Year<br />The first year October 2005 – September 2006 = overall average year. <br />Precipitation (ice, sleet and snow) was 33.0 inches, compared to the 30-year average of 34.5 inches for Portage, Wisconsin.<br />
  8. 8.
  9. 9. 2006 Field Year<br />3 of 4 seasons were drier than normal.<br />Winter was most severe, with precipitation down by one half.<br />Still, the big picture showed this to be an average year for total precipitation. <br />
  10. 10. 2006 Field Year<br />Winter began with a snowfall accumulation of 8 inches through mid-December, followed by a warming trend with highs of 35-40°F and lows of 28-32°F. With only shallow frost in the soil at this time, the snowpack melted and infiltrated with no runoff.<br />Because of the dry winter months, no surface water runoff was measured from November through February for field year 2006.<br />
  11. 11. 2006 Field Year<br />March began with a 5 to 7 inch snowpack and surface water first began flowing through the monitoring equipment on March 4 as temperatures warmed.<br />Snowmelt generated subsequent surface water runoff events on March 7 and 9.<br />The runoff events of March 9 and 12 were a result of melting snow and rain on frozen ground.<br />
  12. 12. 2006 Field Year<br />Through the remainder of field year 2006 there were two more surface water runoff events occurring on July 20 and August 24 as a result of short, intense rainfalls of greater than 1.5 inches each.<br />
  13. 13. 2006 Field Year<br />Runoff Events<br />2006 had very little runoff. Less than 1% (0.01 inches) of total precipitation (33 inches) left the site as surface water runoff.<br />79 % of runoff was during frozen ground conditions.<br />Very little runoff resulted from 3.5 inches of intense summer storms.<br />
  14. 14. 2007 Field Year <br />Second year monitoring on the Breneman farm was another average year for precipitation.<br />Precipitation (ice, sleet and snow) was 32.4 inches, compared to the 30-year average of 34.5 inches for Portage, Wisconsin.<br />Although the annual precipitation was average, 9 months were below average and 3 months were above average precipitation. <br />Winter 2007 was dry again, concluding with slightly more than one half the normal precipitation.<br />August 2007 precipitation was 4.6 inches above normal.<br />
  15. 15.
  16. 16. 2007 Field Year <br />Winter began moderately cool and dry with no surface water runoff measured from November through mid-February for field year 2007.<br />On February 21st, surface water began flowing through the monitoring equipment as warming temperatures melted most of the five to seven inch snowpack, generating a two-day runoff event.<br />This event produced twice as much runoff as the entire 2006 winter season (0.01 inches compared to 0.02 inches), but it is not large when compared with winter runoff events measured at other Discovery Farms Program study sites.<br />
  17. 17. 2007 Field Year <br />Late February temperatures stayed at or below freezing and 10 to 15 inches of snowpack accumulated by the first week in March.<br />A fast warm up began with temperatures climbing from 26°F to near 50°F over six days.<br />This created a significant runoff event, March 10 through March 13, which completely melted the snowpack.<br />This rapid snowmelt, in combination with the frozen soil, produced a very large runoff event (2.85 inches of runoff).<br />
  18. 18. 2007 Field Year<br />Snowmelt runoff, March 12, 2007<br />
  19. 19. 2007 Field Year <br />Temperatures remained in the range of 40 to 60°F through early April. An early April snowfall of five inches melted immediately because of the warm temperatures, yet no surface water runoff was generated as snowmelt water infiltrated into non-frozen soil.<br />
  20. 20. 2007 Field Year <br />Three more surface water runoff events occurred through the remainder of field year 2007:<br /> June 10,<br />June 21, and<br />July 3.<br />All of these short, intense rainfall events delivered extremely<br />low runoff volume, even though the storms each delivered<br />approximately one inch of rain in 20 minutes.<br />
  21. 21. 2007 Field Year<br />Runoff Events<br />For the 2007 season, 9 percent of the total precipitation left the site as surface runoff (2.9 inches of 32.4 inches). 91 percent infiltration.<br />The majority of 2007 runoff at the Breneman farm was the result of rapid snowmelt on frozen soil, March 10-13, which contributed 99 percent of the total annual runoff.<br />
  22. 22. 2006-2007 Water Budget<br />12 total runoff events.<br />5 snowmelt<br />1 rain on snow<br />6 non-frozen<br />99.68 percent of total surface water runoff volume for the 2 year monitoring period was during frozen / snow-covered ground conditions.<br />
  23. 23. Conclusions<br />On the sandy soils of this farm, intense rainfall events did produce runoff on non-frozen ground, but the runoff amount was negligible.<br />Almost all of the total runoff in 2006/2007 from the Breneman farm came as a result of melting snow.<br />99.68 percent of total surface water runoff volume for the 2 year monitoring period was during frozen / snow covered ground conditions.<br />
  24. 24. Conclusions<br />Conservation planning is challenging in this region of the state because the majority of runoff occurs when the ground is frozen and vegetative materials are dead or dormant.<br />Upland conservation systems should be paired with vegetative buffers to keep runoff water near the point of origin in the field and away from surface water.<br />
  25. 25. Conclusions<br />The potential for runoff from sandy soil fields during the non-frozen period is very limited.<br />An intense two-inch rainfall event in July 2006 did not generate significant surface water runoff.<br />There is always the possibility that rain on already saturated non-frozen soil will produce runoff that can affect surface waters. <br />In these gently sloping – sandy soil conditions:<br />Soil and water conservation professionals (and agencies) should prioritize their time and resources towards assisting agricultural producers to implement practices that reduce runoff risks during snowmelt or rain on frozen soil .<br />
  26. 26. Information Available<br />This presentation is the fourth in a series of seven developed to provide the data and information collected at Breneman Farms.<br />All of the presentations, factsheets and briefs are available on the UW - Discovery Farms website.<br /><br />
  27. 27. Information Available<br /><ul><li> There are seven factsheets available for Breneman Farms.
  28. 28. There are eight briefs available for Breneman Farms (2 page summaries of the factsheets).
  29. 29. There are seven presentations available for Breneman Farms. </li></li></ul><li>For Additional Information<br /><br />UW Discovery Farms<br />40195 Winsand Drive<br />PO Box 429<br />Pigeon Falls, WI 54760<br /> 1-715-983-5668<br /> or<br />