Drainage Water Management Assessment Tool

Natural Resources Conservation Service 6/28/2008 Step 1 Place an “x” in the appropriate row in the ”Yes” column DRAINAGE WATER MANAGEMENT INDEX Average* Potential Months Water is Drainage Managed Outflow Yes no Month (in) Jan 2 Feb 2 March 2 April 1.5 May 0.5 June 0.5 July 0.2 August 0.2 September 0.2 October 0.6 November 1.5 December 2 Total Drainage 13.2 Drainage Water Control System Quality Structure Factor ** Factor 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Drainage System Automation Factor 0 0 0 0 0 0 0 0 0 0 0 0 Water Table/Root Zone Monitoring Factor 0 0 0 0 0 0 0 0 0 0 0 0 Estimate of Drainage Water Managed 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 DRAINAGE WATER MANAGEMENT INDEX ==> * - 0 Values Furnished by State NRCS for CSP Watershed of Interest example: rainfall = 38 inches * example: result of total annual drainage =13.2" Prepared for: Located at: Prepared by: Instructions and Guidance on utilization of this tool The above process has been consolidated into a spreadsheet that provides an easy mechanism to follow. The specific steps shown below do not have to be followed in sequence. 1) Select the month(s) you are going to control (manage) the water outflow by placing an X in the proper month(s). 2) Select the indicator for the quality of the drainage system. (this is provided by the landowner and/or DC knowledge from the list that appears) 3) Select the water control structure. None, single elevation, multiple elevation. 4) Select an automation factor. I the system automated? Can I remotely open and close the structure/pump?Yes/no 5) Select a scheduling method. Is there a scheduling method or a means of measuring and tracking soil moisture? Yes/no You may use the selections buttons for each Step to toggle to see how changing the system influences the outcome. You may turn months on and off to see how timing effects the outcome. The index value is yearly potential drainage water managed. It is has no units, and is a relative value. Bigger is better This assessment tool can be completed by the farmer with information provided to NRCS for completing the assessment process. Guidance This assessment tool and documentation is intended for use with all drainage systems. Most common associated Conservation Practices would include Subsurface Drain (606), Surface Drainage, Field Ditch (607), and Surface Drainage, Main or Lateral (608), Structure for Water Control (587), Pumping Plant (533), and Drainage Water Management (544). There may be other companion or associated conservation practices or appurtenances. More common applications would be associated with subsurface drainage systems (tile drains), surface drainage systems (a series of lateral drains that can be controlled (commonly referred to as controlled drainage), or surface drainage systems where drainage is achieved by intensive land grading and precision land leveling where the topography is flat or the soil and elevations are such that surface drainage systems are the preferred technical solution. Water control structures are not limited to gravity flow. The issue is control of the drainage water. The water control structures can be, but are not limited to, gates, valves, flashboard riser structures, weirs, pumps and similar mechanisms that can be used to store or control the volume, timing, and depth of water flow. This assessment tool may also be considered for evaluation and assessment of drainage outflow from normally operated irrigation systems. Many irrigation systems have tailwater and drainage flows as a result of irrigation water applications. This is a normal occurrence because of topography, soils, salinity management, or other considerations. 606), Surface tile drains), topography ainage water. nage outflow Conservation Security Program 2005 Drainage Water Management Process Documentation and Background This assessment tool and documentation is intended for use with all drainage systems. Most common associated Conservation Practices would include Subsurface Drain (606), Surface Drainage, Field Ditch (607), and Surface Drainage, Main or Lateral (608), Structure for Water Control (587), Pumping Plant (533), and Drainage Water Management (544). There may be other companion or associated conservation practices or appurtenances. More common applications would be associated with subsurface drainage systems (tile drains), surface drainage systems (a series of lateral drains that can be controlled (commonly referred to as controlled drainage), or surface drainage systems where drainage is achieved by intensive land grading and precision land leveling where the topography is flat or the soil and elevations are such that surface drainage systems are the preferred technical solution. Water control structures are not limited to gravity flow. The issue is control of the drainage water. The water control structures can be, but are not limited to, gates, valves, flashboard riser structures, weirs, pumps and similar mechanisms that can be used to store or control the volume, timing, and depth of water flow. This assessment tool may also be considered for evaluation and assessment of drainage outflow from normally operated irrigation systems. Many irrigation systems have tailwater and drainage flows as a result of irrigation water applications. This is a normal occurrence because of topography, soils, salinity management, or other considerations. 1. Our desire is to incorporate Drainage Water Management into CSP with a view toward improving water quality. Drainage water has the potential to transport nutrients and pesticides off-site. N and P are of particular concern. In some instances drainage water can transport liquid manure off-site. The volume of water transported to surface water systems can equal surface runoff volumes in many instances. 2. We do not have the capability or desire under this program to quantify the contaminant concentrations. Research data which would allow estimation of contaminant levels are not available or are inconsistent. Concentration is also influenced by the contaminant's source (i.e., what has been applied? and when?). Our ultimate goal should be incorporating the nutrient management (form, rate, timing) into surface water runoff, ground water runoff, and subsurface drainage as well as implications for other resource concerns such as air quality. At this time we do not have the ability to perform an assessment that incorporates all of these potential evaluations into a single, comprehensive assessment tool that can be easily performed at the field level. 3. The approach taken: a. Drainage Water Management is directly related to water quality. More specifically… improved downstream water quality is a direct result of reducing outflows from controlled drainage systems. b. Drainage Outflow is a function of: i. Soil ii. Ability of drainage system to intercept drainage water and convey to an outlet. c. Drainage water management is a function of: i. Amount of drainage water retarded or stored in the soil profile and/or the time drainage water is held or stored allowing chemical reduction processes to take place. d. The amount of Drainage Water Managed is a function of: i. The ability of the drainage system to distribute and effectively store drainage water ii. The amount of drainage water potentially available ii. The amount of drainage water potentially available iii. The time this water is stored/managed iv. The ability of the system to be managed which is normally associated with the water control structure capability e. Rainfall (by Month) can be partitioned into uncontrolled runoff, water used by the crop or stored in the root zone, and water that is drained. Tools that could be used to develop this partitioning include SPAW and DRAINMOD. SPAW runs can be made which yield the amount of rainfall, used by the crop, and drainage or deep percolation. Then determine the amount of water by month that could possibly be drained. For the 2005 program year time does not permit detailed evaluations of each local watershed. Values will be provided to the states based on SPAW evaluations. States can supplement if more detailed data is available. f. We will assume drainage and deep percolation are removed by the drainage system installed or at least some portion of it. 4. Process used: 1) The primary basis is the amount of potential drainage water. It may be managed, controlled, or open. Open is not managed. 2) A water control structure is needed in line somewhere...open ditch, drainage main, drainage lateral, tile, surface, precision land leveling...irrigation outflows. 3) What is the ability to manipulate water control structure? Single elevation (on or off) or multiple elevation control (variable elevations). 4) Automation of structure? Can we call it and turn it on or off remotely? (Mostly for the future) 5) Scheduling? Do we have some soil moisture measurement or tracking system that clearly tells me when to open and close and at what elevation? (mostly for the future) 6) We need to know the quality of the drainage system. Intensive pattern drainage systems that are relatively flat, with relatively flat topography that covers the entire field is easier to manage and probably more effective than a rolling or steeper field. So the key factors are the soil and the slope, spacing, size, depth and placement of the drains. How do I get at these and stay within my 5 to 10 minute assessment time? That ultimately becomes the key issue. 7) The most important management item is when do we turn it on...set the water control elevation...turn it off? Instructions and Guidance on utilization of this tool The above process has been consolidated into a spreadsheet that provides an easy mechanism to follow. The specific steps shown below do not have to be followed in sequence. 1) Select the month(s) you are going to control (manage) the water outflow by placing an X in the proper month(s). 2) Select the indicator for the quality of the drainage system. (this is provided by the landowner and/or DC knowledge from the list that appears) 3) Select the water control structure. None, single elevation, multiple elevation. 4) Select an automation factor. I the system automated? Can I remotely open and close the structure/pump?Yes/no 5) Select a scheduling method. Is there a scheduling method or a means of measuring and tracking soil moisture? Yes/no You may use the selections buttons for each Step to toggle to see how changing the system influences the outcome. You may turn months on and off to see how timing effects the outcome. The index value is yearly potential drainage water managed. It is has no units, and is a relative The index value is yearly potential drainage water managed. It is has no units, and is a relative value. Bigger is better This assessment tool can be completed by the farmer with information provided to NRCS for completing the assessment process. The keys: • We are relying heavily on landowner self-assessment in determining quality of drain system and how and when the system is operated. We are using a series of questions and answers to arrive at this representation of slope, depth, spacing, functioning, soil etc. This is consistent with the CSP approach to conservation. • We need to do more development of this technology in the future. Efforts are underway to work with the Drainage Water Management Task force and others. Refinement will be accomplished but we need to keep the assessment process simple, farmer friendly, and not time consuming.