From Harford County government:
The Harford County Dept. of Parks & Recreation has reopened the Ma & Pa trailhead at Williams Street in Bel Air, which had been closed for emergency repairs to a culvert along the trail. All other access points to the trail remained open during construction and the repairs were completed ahead of schedule.
Storms over the years had caused significant erosion to the culvert located just past the Williams Street trailhead. The repairs were necessary to prevent further damage to the culvert, and ultimately, the trail.