Description: The purpose of this project was to construct a passive treatment system at the Little D Discharge in the Morgan Run watershed. Located approximately 8 miles southeast of Clearfield, this is the downstream-most discharge affecting Morgan Run. The abandoned mine drainage (AMD) in this area was created after the site was strip mined and abandoned by Chews Contracting Little D Job, SMP#17813143. Previous surface reclamation at the site was performed, but that has not improved the water quality of the discharge. Since this site was abandoned, all bonds were forfeited and the discharge became a priority treatment area for the Moshannon District Mining Office. The Little D Discharge is a deep mine discharge with a pH measured at 3.5. Average water quality of the discharge was: 114 mg/L of acidity, 1.8 mg/L of aluminum, 4.5 mg/L of iron, 39.7 mg/L of manganese, and 450 mg/L of sulfates. The treatment system was design to treat 25 gpm. The treatment system installed at the site is anticipated to improve water quality of the discharge by adding 101 mg/L of alkalinity to the system. The added alkalinity will increase the pH of the discharge allowing metals to precipitate. Treatment system components selection and sizing was provided by New Miles of Blue Stream, original design plans were provided by WHM Consulting, Inc. & the BAI Group, and the construction was completed by E.M. Brown, Inc. The Little D passive treatment system includes an equalization basin, vertical flow wetland, settling pond, horizontal flow limestone cell, and upgradient diversion berm diverting upslope runoff around the site.