Improved Surface Irrigation
alternative practice names:
Flood Irrigation; Furrow Irrigation; Border Irrigation; Basin Irrigation
Surface irrigation is the predominant method for irrigating forages in the U.S. It encompasses both flood irrigation (where flat fields are uniformly flooded) and furrow irrigation (where water is directed into furrows or trenches between rows of crops). In both methods, water is allowed to seep into the soil and irrigate the plants.
To enhance the efficiency of surface irrigation, farmers employ various practices to improve water distribution and minimize wastage. Water released into furrows often saturates the soil unevenly along the furrow’s length. The upper parts of the furrow receive water for a longer period, leading to deeper percolation into the soil and inefficient use of water. To address these challenges, farmers use the following techniques:
In fields that can be precision graded: Improving water distribution and reducing deep percolation is crucial. In precision-graded fields, water is released until it reaches the end of the furrow, which can result in excessive irrigation at the upper end of the field. This leads to uneven water distribution and excess water that percolates below the root zone, which the crop cannot utilize. By increasing the speed at which water travels from its source to the opposite end of the field, farmers can enhance water distribution, shorten irrigation durations, and improve overall water use efficiency.
In fields that cannot be precision graded: Preventing surface runoff is critical. Farmers use tailwater recovery systems or diking methods to prevent water waste in fields that cannot be economically leveled. Tailwater, which is the runoff from the end of the field, can be collected, stored, and reused on other fields, thereby improving overall irrigation efficiency on the farm. Tailwater is not lost but rather redirected and utilized effectively through sophisticated systems many producers implement.
When evaluating improvements to surface irrigation systems, it is essential to understand why these methods remain popular in arid landscapes. Farmers continue to favor traditional approaches for several compelling reasons:
Simplicity: Flood and furrow irrigation methods are relatively simple and can be implemented with basic infrastructure. They are straightforward to manage and require less technical expertise compared to more advanced systems.
Lower initial cost: These methods require lower initial investments in equipment and infrastructure than sprinkler systems, making them more accessible for farmers with limited capital.
Reduced evaporation: Flood and furrow irrigation typically result in less water evaporation compared to sprinkler or pressurized systems. In furrow irrigation, water is applied less frequently and is stored deeper in the root zone, which reduces evaporation losses. Although some water may be lost to deep percolation, recovering this water through wells can improve efficiency. If impermeable layers impede groundwater infiltration, pressurized systems may offer better water efficiency.
Salt management: Flood irrigation helps manage soil salinity by leaching excessive salts out as water percolates through the soil, which is beneficial for maintaining soil fertility and productivity.
The advantage of these practices is that they require minimal additional infrastructure. Farmers can improve furrow irrigation efficiency without the significant investment needed to upgrade to different irrigation systems.
FARM SIZE
When used, typically found on farms of the following sizes:
All Sizes

Practice Benefits
Reduced deep percolation: Shortening the time it takes for water to travel to the end of the furrow minimizes excess water application at the field’s upper end and improves water distribution uniformity.
Reduced runoff risk: These improvements help reduce erosion and nutrient runoff, promoting better soil and water conservation.
Labor savings: Enhanced systems significantly reduce the labor involved in managing irrigation.
Enhanced irrigation efficiency: These improvements optimize overall irrigation efficiency by reducing water application, improving distribution uniformity, and minimizing deep percolation.

Implementation Insights
Site-specific or Farm-specific requirements

In most cases, there are no specific site or farm requirements.
Required Capital Expenditures (CapEx)

High-flow turnouts: High-flow turnouts are large openings in the ditch; they are an alternative to siphon tubes for achieving rapid water flow through the furrow and decreasing the duration of irrigation.
Surge flow valves: Water is pulsed on and off in planned time intervals. Each surge of water causes soil particles to partially seal the furrow and for water to travel more rapidly down the furrow during the next surge. The alternating wetting results in higher uniformity than by using a continuous flow. The impact is more pronounced during the first irrigation event of the season and declines as the furrow naturally "seals."
Tailwater recovery pits: Irrigation water that would otherwise run-off the field is captured and reused. Tailwater can either be pumped back onto the field it derived from or channeled to another nearby field.
Required Operational Expenditures (OpEx)

Precision-leveling or zero-grading: This technique involves creating a uniform surface with a slight grade, based on soil type and infiltration rates. Precision leveling or zero-grading removes irregularities in the field’s topography, which helps to ensure that water is distributed more evenly across the field. This reduces water losses by minimizing areas where water might accumulate or drain away unevenly, improving overall irrigation efficiency.
Furrow compaction: Using a compaction roller to firm and smooth the furrow wall and bottom can indeed reduce soil infiltration rates. By decreasing infiltration, water advances more rapidly and uniformly along the furrow. This helps to ensure that water is distributed more evenly along the length of the furrow, reducing water losses due to uneven distribution.
Implementation Considerations

Technical knowledge: Irrigators may need technical assistance to assess whether specific techniques for improving surface irrigation are suitable for their crops, soil conditions, and regional factors. This expertise is essential for making informed and effective irrigation decisions.
Knowledge of application rate: Many irrigators lack the ability to measure the exact amount of water applied through surface irrigation. Decisions, including cut-off times, are often based on visual estimates rather than precise measurements. The absence of flow meters and automation systems can limit the ability to apply water accurately and efficiently.
Financial Considerations and Revenue Streams
FEDERAL COST-SHARE PROGRAM
Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP) and the Conservation Stewardship Program (CSP).
Related EQIP Practice Standards: Irrigation water management (449), Irrigation system, surface and subsurface (443), Irrigation and drainage tailwater recovery (447), Irrigation land leveling (464).
Related CSP Enhancements: Advanced tailwater recovery (E447A), Complete pumping plant evaluation for water savings (E449A), Advanced automated IWM – Year 2-5, soil moisture monitoring (E449C), Advanced automated IWM – Year 1, Equipment and soil moisture or water level monitoring (E449D), Intermediate IWM— Year 1, equipment with soil moisture or water level monitoring (E449F), Intermediate IWM— Years 2-5, soil moisture or water level monitoring (E449G), Intermediate IWM— Years 2 -5, using soil moisture or water level monitoring (E449H), IWM - Year 1, retrofit equipment with speed control on sprinkler irrigation system (E449I).
Notes:
Check with the local NRCS office on payment rates and practice requirements relevant to your location.
Additional Resources
Article: Flood Irrigation of Alfalfa: How Does it Behave (Alfalfa Symposium)
Article: Managing Furrow Irrigation Systems (University of Nebraska–Lincoln)
Article: Surface Irrigation Systems (FAO)
Presentation: Improving the Efficiency of Surface Irrigation Systems in California (University of California Cooperative Extension)

Environmental Impacts
CONSERVES WATER
Improved surface irrigation techniques minimize deep percolation¹ by optimizing water application and distribution.
MAY IMPROVE WATER QUALITY
By reducing water runoff, improved surface irrigation methods help conserve water and prevent soil erosion, which in turn reduces the loss of nutrients and sediments.
────────────────
¹ Deep percolation refers to the movement of water below the root zone of plants and into deeper layers of the soil. While some deep percolation can be beneficial for recharging groundwater aquifers, excessive deep percolation is often seen as a form of water loss in irrigation, as the water moves beyond where it can be used by crops. In some states, such as California, deep percolation is encouraged during certain times of the year through managed aquifer recharge (Flood-MAR) programs. During winter months, when stream flows are higher and reservoir surpluses exist, excess water is deliberately diverted to flood fallow fields, allowing it to percolate deeply and replenish groundwater supplies. This approach helps mitigate the impact of reduced snowpack and lower summer stream flows, while aligning with groundwater management efforts under laws like California's Sustainable Groundwater Management Act.

Alignment with FARM Program
FARM Environmental Stewardship (ES) V2-V3 Alignment
The optional FARM ES Conservation Practice Questionnaire (CPQ) asks about irrigation stewardship methods.
Contents
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
Surface irrigation is the predominant method for irrigating forages in the U.S. It encompasses both flood irrigation (where flat fields are uniformly flooded) and furrow irrigation (where water is directed into furrows or trenches between rows of crops). In both methods, water is allowed to seep into the soil and irrigate the plants.
To enhance the efficiency of surface irrigation, farmers employ various practices to improve water distribution and minimize wastage. Water released into furrows often saturates the soil unevenly along the furrow’s length. The upper parts of the furrow receive water for a longer period, leading to deeper percolation into the soil and inefficient use of water. To address these challenges, farmers use the following techniques:
In fields that can be precision graded: Improving water distribution and reducing deep percolation is crucial. In precision-graded fields, water is released until it reaches the end of the furrow, which can result in excessive irrigation at the upper end of the field. This leads to uneven water distribution and excess water that percolates below the root zone, which the crop cannot utilize. By increasing the speed at which water travels from its source to the opposite end of the field, farmers can enhance water distribution, shorten irrigation durations, and improve overall water use efficiency.
In fields that cannot be precision graded: Preventing surface runoff is critical. Farmers use tailwater recovery systems or diking methods to prevent water waste in fields that cannot be economically leveled. Tailwater, which is the runoff from the end of the field, can be collected, stored, and reused on other fields, thereby improving overall irrigation efficiency on the farm. Tailwater is not lost but rather redirected and utilized effectively through sophisticated systems many producers implement.
When evaluating improvements to surface irrigation systems, it is essential to understand why these methods remain popular in arid landscapes. Farmers continue to favor traditional approaches for several compelling reasons:
Simplicity: Flood and furrow irrigation methods are relatively simple and can be implemented with basic infrastructure. They are straightforward to manage and require less technical expertise compared to more advanced systems.
Lower initial cost: These methods require lower initial investments in equipment and infrastructure than sprinkler systems, making them more accessible for farmers with limited capital.
Reduced evaporation: Flood and furrow irrigation typically result in less water evaporation compared to sprinkler or pressurized systems. In furrow irrigation, water is applied less frequently and is stored deeper in the root zone, which reduces evaporation losses. Although some water may be lost to deep percolation, recovering this water through wells can improve efficiency. If impermeable layers impede groundwater infiltration, pressurized systems may offer better water efficiency.
Salt management: Flood irrigation helps manage soil salinity by leaching excessive salts out as water percolates through the soil, which is beneficial for maintaining soil fertility and productivity.
The advantage of these practices is that they require minimal additional infrastructure. Farmers can improve furrow irrigation efficiency without the significant investment needed to upgrade to different irrigation systems.
Practices and technologies
Improved Surface Irrigation
alternative practice name:
Flood Irrigation; Furrow Irrigation; Border Irrigation; Basin Irrigation