Monocacy Creek is one of only 56 limestone streams in the state of Pennsylvania. Its watershed encompasses 48.8 square miles in eastern Lehigh and western Northampton counties, just south of Blue Mountain in southeastern PA. Its headwaters lie in the slate belt, near the borough of Chapman (elevation 900ft.). From Chapman, the Monocacy follows a meandering 20.3-mile course through the limestone Lehigh Valley, to its confluence with the Lehigh River in the city of Bethlehem (elevation 212 ft.).
The upper third of the watershed consist of three tributaries that run through the wooded, hilly terrain of the slate belt. Near the borough of Bath, the geology of the watershed changes from slate bedrock to limestone bedrock. Over the next six miles, the Monocacy meanders past farms and houses until it reaches Camel's Hump in Bethlehem. This section of the Monocacy is referred to as a losing stream. In other words, stream flow is constantly being lost to subsurface ground water flow. In fact, during the dry summer months, the section of the Monocacy between Stueben Road and Camel's Hump sometimes dries up.
At Camel's Hump the Monocacy suddenly resurfaces. Camel's Hump is an igneous outcrop of impermeable Byram Gneiss that acts as an underground dam, forcing all of the ground water back to the surface. However, there is not one big spring that suddenly replenishes the Monocacy with surface water. Instead, there are hundreds of small springs over about a mile length of the stream, in an area called the Archibald Johnston Conservation Area. From this point downstream to its confluence with the Lehigh River, the Monocacy is a Class A wild trout stream.
The demographics of the watershed change at Camel's Hump, as farm fields give way to the suburbs surrounding the City of Bethlehem. Most of this section of the Monocacy flows through private property, and the stream is not stocked. However, the Monocacy supports an excellent population of wild brown trout, and property owners generally allow access if common courtesy is practiced. Parking is the biggest problem, so please use established parking spaces when exploring the Monocacy.
There are also two City of Bethlehem parks along the Monocacy where ample parking is provided. Monocacy Park, including Monocacy Nature Center, is located on Illick's Mill Road and Sand Island Park is located at the confluence with the Lehigh River.
The Monocacy's well preserved riparian corridor keeps the creek shaded and cool during the summer months and provides fantastic habitat for migrating and nesting birds. Area birders have documented over 80 species of birds annually along the banks of the Monocacy.
But all is not rosy for the Monocacy. Recent studies by the Wildlands Conservancy have documented concentrations of nitrates and phosphates far in excess of EPA guidelines. Increased development and poor farming practices are most likely causing these high concentration, and the Monocacy Creek Watershed Association is committed to reducing these levels. The Association has already completed one stream fencing project, and is planing others. Educating homeowners about proper landscape maintenance is another high priority.
Please help preserve and enhance the Monocacy by joining our cause. For information, E-mail Phil Burtner at phil_burtner@hotmail.com.