Almost any area in the state of Ohio can be considered for reuse of renovated wastewater. Irrigation sites fall into three categories:
Although site characteristics make some areas more suitable for irrigation than others, provisions can be made to allow irrigation in areas that are less than ideal. Table 1 presents the characteristics of an ideal site, as well as strategies for overcoming site limitations.
When selecting a site for irrigation, keep cost trade-offs in mind. Land cost is an obvious factor to consider. Cost to transport the wastewater to the site may present some important trade-offs. Pumping treated wastewater to an upland site is more costly than gravity flow to a lowland site. The cost of a stream crossing to reach a possible site may outweigh the higher land costs nearby. Restricted access and remote sites have lower treatment requirements, resulting in lower treatment costs.
| Table 1. Site characteristics for wastewater reuse site | ||
|---|---|---|
| Site characteristic | Ideal | Provisions if not ideal |
| Soil permeability | Greater than 0.2 inches/hour | More acres are needed for irrigation |
| Slope | Less than 15 percent for cultivated fields | Runoff control measures (consult with Natural Resources Conservation Service) |
| Less than 20 percent for turf or pasture | ||
| Less than 40 percent for timber | ||
| Surface water | Not applied to wetlands, streams, or waterways | |
| Floodplains | More than 10-year flood return period | Storage or alternate application site during flood event |
| Depth to groundwater | 1 foot to soil mottling or other evidence of groundwater | Storage or alternate management strategy during high groundwater periods Drainage systems may also be an option |
| Depth to bedrock | ||
| Agricultural and restricted access | More than 2 feet | If site is filled, fill material must be in place for at least 4 years before reevaluation for suitability |
| Unrestricted access | More than 1 foot |