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3.1. Root clogging
3.1.1. Root clogging occurrence
Roots of annual crops do not pose a risk of drain clogging when pipes are installed properly between 2.5- and 4-ft depth. Some smaller younger roots enter the drain pipes, but they die after plant harvest and slowly decay, and their remains wash away.
When poor installation of drain pipes results in an off-grade dip or hump in the pipe, water will stand in the pipe, thereby promoting increased root growth in and around the pipe. Also, improper connections can increase the chance of root clogging. For example, when tap-tees are not correctly inserted, they can lead to an obstruction that can catch the younger roots flowing with water in the pipe. Then, the roots can accumulate and clog the pipe, or significantly reduce the flow (Figure 2). Use fittings that have minimal parts sticking into the pipe.
If radish cover crops grow too much, they may cause drain clogging with their long roots. Avoid planting radish cover crops too early to prevent their roots from getting too long. Early planting such as with prevented planting, may lead to radish roots reaching and clogging the pipes. Radishes planted in late August or early September should not pose a risk of drain clogging for drainage systems in good condition.
Perennial crops may cause root clogging depending on the type of vegetation. For example, when drain pipes need to go through trees or shrubs, use a nonperforated pipe to prevent root entrance.
3.1.2. Root clogging mitigation methods
For addressing root clogging, flushing the younger weaker crop roots with a high-pressure jet nozzle (also known as jetting) helps remove some of the crop roots. With stronger roots or tree roots, jetting may need to be combined with rodding to break up the roots. Consider that, generally, rodding takes more time than jetting and is useful to remove clogging closer to the outlet. If these solutions do not work, new drain pipes may need to be installed. Contact a local sewer, plumbing, or septic tank cleaning company for jetting (Figure 3).
3.1.3. Root clogging preventive measures
A good installation reduces the chance of root clogging (Section 3.1.1). If the field is suitable for controlled drainage, it can reduce the risk of root clogging by keeping the area around the drains saturated during some of the growing season.
The area in the vicinity of the outlet pipe should be kept clear from brush growth because brush roots can follow the wall of the outlet pipe in the upstream direction. Then, they can enter the pipe through the first connection and clog the pipe. A good practice is to mark the area in the vicinity of the outlet pipe so that the site can be easily found and the brush removed.