As required by NYSDEC and ACOE permits, the GCSWCD must dewater the project site. On this site, a 12" diesel pump was placed at the top of the project, with a water inflated barrier used as a cofferdam. The upstream flow was intercepted and pumped via a 1400 ft long, 12" aluminum pipe to a point below the work. At the outfall, a plastic lined ditch was used to control the flow back into the stream and to prevent erosion at the outfall. Pumping continues around the clock until the project is finished. Typically dewatering is 25% of the total project costs.   

During the project, steps must be taken to control sediment releases from the work area. On this project, a 10" electric pump with duel 6" pipelines were used to pump all turbid water to a grassy area on the floodplain where it was filtered before reentering the stream.

The first task in the project construction, is to establish the basic channel shape. The new planform, cross section and profile are constructed using cuts and fills.  For this project, a pond was dug on the floodplain, which yielded approximately 2,600 cu.yds. of borrow material. 

The contractor accomplished this using 2 D-8 and a D-9 dozers, which are the most efficient way to move material when it is a short push.   The majority of the earth pushing was accomplished in about three days. The new channel was then ready for construction of the rock structures.

When the new stream channel is roughed in, the excavators begin the constructing the rock structures. On this project, three 45,000 lb. excavators were needed, two having hydraulic thumbs and one without a thumb. During construction of the rock vanes, cross vanes and w-weir, GCSWCD closely observed the contractors work and direct placement of the rock.  The rocks used averaged 3x4x6 feet in dimension and weighed anywhere from 3 to 12 tons.  On this project vane arms were placed on slopes of  7% or bit steeper. The GCSWCD has since learned from construction projects that vane arms are more effective if placed on a 4% slope.

On the Maier project, the GCSWCD  wanted to try a variety of methods to establish riparian vegetation. In some places, sod mats salvaged  from the borrow  area were placed in a 10' wide band just above bankfull. The Contractor also used a front end loader and excavator to transplant large clumps of willows from a drainageway.  Once the dormant season arrived, the Contractor installed live fascines, while the GCSWCD and Trout Unlimited volunteers planted additional stakes. The NYC Watershed Agricultural Program  planted a riparian buffer of mixed trees and shrubs. The GCSWCD will plant additional materials in 2001.