Incorporation of Soil Health Engineered Measures on MnDOT Construction Projects and Resilient Stormwater Management

Summary:

After construction is complete, the soil at highway construction sites is often highly degraded and compacted. Post-construction soils can produce much higher runoff rates than either prior to construction or predicted for typical vegetated areas. Establishing vegetation may be difficult due to poor soil conditions and, where vegetation is sparsely established, degraded soils continue to deliver large volumes of runoff, sediment, and nutrient loads to local waters. Two recent research projects led by the research team have shown that use of proprietary or natural organic soil amendments (composts) have the potential to restore soil health and improve post-construction vegetative growth by increasing soil structure, nutrient availability, and water holding capacity. However, the long-term effects on overall soil health (including biological properties) by adding organic matter (e.g., compost mainly in this case) and planting deeper rooted native vegetation warrant further study to determine whether biological, chemical, and physical mechanisms can be implemented to create permanent beneficial soil health outcomes. The overall goal of this research is to define preconstruction baselines of soil health from reference locations, determine optimized design and field implementation options to rapidly return soils to original baseline health indices using organic amendments (e.g., compost), and how these amendments can benefit transportation requirements and resilient stormwater treatment. This goal will be achieved through the completion of three objectives: (1) evaluate resilience to water availability through organic amendment (e.g., compost) addition through greenhouse stormwater experiments; (2) optimize amendment loadings based on resilience; (3) develop a “recipe” for improving the health of poor soils based on soil health measurements, by amending the soil with compost (other organics such as biochar etc. can also be used upon discussion with Technical Advisory Panel (TAP)). Based upon these results, a quantification of benefits provided through soil health restoration and the development of implementable guidance for roadside soil health restoration techniques can be accomplished.

Final Deliverables:

Related Materials:

• New Project: Engineering Post-Construction Soil Composition to Support Resilient Stormwater Management  (Blog Post)

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