The site of Arcata Marsh, which is located adjacent to the city’s wastewater plant, was used by lumber mills and as a landfill until 1973 when the landfill was closed and capped. In 1974 California passed strict laws on the discharge of wastewater into bays and estuaries. Rather than building a new wastewater plant experiments were conducted on the effectiveness of running the partially treated wastewater through a natural system of marshes. The idea worked well and now the marsh is a popular place for walking, jogging, and bird watching. Five miles of innerconnecting trails that loop around the ponds allow visitors to choose a walking distance.