What is Drainage Water Recycling?
Drainage water recycling is a water management practice that captures water drained from agricultural fields, specifically where drainage tiles are in common use. When this water is stored in ponds, reservoirs, or even drainage ditches it can be used to irrigate crops during seasonal dry periods or short-term droughts.
Across some of the most prolific agricultural regions in the US, there has historically been a pattern of heavy spring precipitation, followed by long, dry summers. As weather patterns become more extreme, spring rains are expected to become heavier but less frequent, and summer dry periods are predicted to be hotter and dryer. Under these conditions, farmers often can’t rely on consistent water availability throughout the season. Capturing tile drainage for re-use as irrigation water can make all the difference when nature isn’t supplying enough water and alternative water supplies are inadequate. The ability to alleviate drought stress during the summer, even partially, can have an enormous impact on harvest yield and quality.
What is Tailwater Recycling?
Tailwater, or agricultural wastewater, is excess water that is not absorbed by soil but runs off agricultural fields after irrigation or precipitation events and flows downslope beyond the fields or pools in low areas. While many farmers will intentionally, slightly overwater fields in order to ensure the soil is properly saturated, any water that flows across the soil will pick up pollutants and shouldn’t be permitted to drain directly to surface waters or leach through to groundwater.
Farmers who choose (or are required) to minimize surface runoff into waterways may employ berms or small dams to prevent runoff from exiting the field, allowing it to pool downslope instead. This minimum-effort treatment can damage crops which are left for extended periods in standing water. Reducing irrigation to alleviate that problem, on the other hand, may result in under irrigated crops on the upper end of the slope. A more effective solution would be to allow proper drainage and divert the excess water back to the field for reuse.
As the effects of widespread weather changes become more apparent, water scarcity has become a significant concern for farmers around the world, especially when the supplies that do exist are increasingly polluted. The combined pressures of dwindling fresh water supplies and spikier rainfall patterns are making it necessary to not only capture agricultural tailwater, but to treat it as a valuable resource and make maximum use of it.
