Volunteers map the San Pedro for 20th Year Running
Hereford — In the early Sunday morning chill, four women trudged through the ankle-deep sand of the San Pedro riverbed, clipboards and GPS devices in hand. Their mission: to take over where their fellow citizen scientists had left off the day before by mapping the nearly 5 ½-mile stretch of the river lying between Highway 92 in Hereford and Palominas.