The Construction & Evaluation of Biochar Amendments to Stormwater Dry Retention Ponds

Researcher(s)

  • Jelani Bryant, Environmental Engineering, Delaware State University

Faculty Mentor(s)

  • Paul Imhoff, Civil, Construction, & Environmental Engineering, University of Delaware

Abstract

Using biochar as a soil amendment in dry retention basins presents a promising approach to enhance soil properties and improve stormwater management. This study aims to analyze the effects of biochar on soil compaction and water infiltration within dry retention basins. A dry retention basin is a dry depression in the land used to detain stormwater for a short period of time to allow particles and pollutants to settle and stormwater to infiltrate. Biochar is a charcoal-like soil amendment made of combustible biomass in an oxygen-limited environment that, when added to soils, can increase soil health properties like drainage, carbon sequestration, soil aeration, and decrease soil compaction. Biochar was installed in a dry detention basin in 2022. Measurements taken were to see if the biochar addition had taken any effect on soil in designated treatment plots of 4% and 8% biochar, tilled-only plots, and control plots that were left unamended. A compaction test using a penetrometer was conducted at a depth of 1 foot (300 millimeters) to evaluate the impact of biochar on soil penetration resistance. The results indicated a significant reduction in soil compaction in the biochar-amended plots compared to the control plots, suggesting that biochar can effectively alleviate compaction effects and thus promote the growth of plant roots. In addition, a Modified Philip-Dunne (MPD) Infiltrometer was used to measure the water infiltration rate in the soil. The findings demonstrated a notable increase in water infiltration rates in the biochar-amended plots, indicating that biochar enhances the soil’s capacity to absorb and retain water. Overall, the study highlights the potential of biochar as an effective soil amendment in dry retention basins, improving both soil structure and water infiltration. These improvements can contribute to better stormwater management, and enhanced water quality in urban environments. Further research is recommended to explore biochar application’s long-term effects and scalability in various soil types and climatic conditions.