Rule 15-15-77-7-5.7.10 - Minimum Specifications for the Spray Field1. Spray irrigation systems may not be installed in drain ways, swamps, marshes, floodplain, concave landscape positions or other areas which would be prohibited.2. Treated effluent shall be sprayed evenly over the entire spray field area with non overlapping patterns. The spray field shall consist of a minimum of three (3) spray heads.3. The effluent distribution system shall be designed, constructed and maintained to provide for even distribution of effluent throughout the spray field.4. Surface runoff of sprayed effluent from the spray field area shall not be permitted. Rainwater shall be diverted away from the spray field area.5. The spray field area shall be designed and operated to prevent surface accumulation of sprayed effluent.6. In order to prevent entrapped air causing serious problems pipelines shall be routed on contour, downhill or even uphill but not up and downhill along the same section of pipe.7. The size of the spray field area shall be determined by soil texture and slope of the site to be sprayed (See Table 1). Table I SIZING Spray Irrigation
Results of the Soil and Site Evaluation
| Soil Textural Class | Ribbon Lengths (Inches) | EPA Manual Application Rate GPD/Ft2 | Absorption Area in Ft2/Bedroom | Additional Absorption Area Over 2 Persons Per Bedroom |
| Slope | Slope |
| 0 to 8 % | 9 to 12% | 13 to 16% | 0 to 8 % | 9 to 12% | 13 to 16% |
| Gravel | NOT SUITABLE |
| Coarse and Medium Sand Fine and Loamy Sand Sandy Loam | < 0.5 | 1.2 0.8 0.6 | 694 | 928 | 1,040 | 347 | 478 | 520 |
| Loam Silt Loam Sandy Clay Loam | <0.5 - 1.0 < 0.5 - 1.0 1.0 - 2.0 | 0.45 | 1387 | 1734 | 2323 | 694 | 867 | 1162 |
| Silt Clay Loam Clay Loam Sandy Clay | 1.0 - 2.0 1.0 - 2.0 >2.0 | 0.2 - 0.3 0.2 - 0.3 - | 2782 | 4637 | 6951 | 1391 | 2319 | 3476 |
| Silty Clay Clay | >2.0 | - | 6951 | 8693 | 11588 | 3476 | 4347 | 5794 |
Table II FILL MATERIAL
| Seasonal High Water Table Depth (inches) | ...with a Restrictive Horizon/Layer (inches) | ...without a Restrictive Horizon/Layer (inches) |
| 0 | 6 | 12 |
| 1 | 5 | 11 |
| 2 | 4 | 10 |
| 3 | 3 | 9 |
| 4 | 2 | 8 |
| 5 | 1 | 7 |
| 6 | - | 6 |
| 7 | - | 5 |
| 8 | - | 4 |
| 9 | - | 3 |
| 10 | - | 2 |
| 11 | - | 1 |
| 12 | - | - |
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15 Miss. Code. R. 15-77-7-5.7.10