Progress Update - May 10, 2016

Despite the seemingly endless rain, construction continues on the KVT project. With stream restoration complete, we've made the first production steps along the trail itself, starting with the underground work.

New storm water and drainage pipe will be installed throughout the trail.  Much like the gas line replacement, storm drain installation is challenging work, particularly with existing storm drains and utility lines running the full length of Klingle Road.

The first storm water pipe installation started last week, replacing a failed brick masonry culvert that outfalls into Klingle Creek. Scroll through the slideshow below to see the construction sequence.

Work within the Porter Street Interchange has been a key focus area over the past few weeks. Sidewalk installation along the Klingle Road to Porter Street Connector Ramp took place last week (Stage 2A in the graphic below).

Click through the slideshow below to see the sequence of construction along the connector ramp.

Over the past few weeks, the KVT contractor has also focused on constructing new wheelchair and bicycle ramps within the interchange, which are installed in accordance with DDOT and Americans with Disabilities Act standards.

Washington Gas is also progressing gas main replacement east towards Porter Street. Excavation and pipe replacement is now taking place within the active segment of Klingle Road, as seen in the left photo below.

Progress Update - February 8, 2016

We've had a busy few weeks at the KVT project. Stream restoration work is nearing completion, and we are starting to prepare for the next phases of the project, to include roadway demolition, storm water and drainage construction, and trail construction.

It should come as no surprise to those in the DC area that the ever-changing weather has had a major impact on the project over the past three weeks.

First there was ice...

...then came the snow...

...which melted and was quickly washed away by the rain.

That said, the new stream features in Klingle Creek held up very well considering they are unfinished and not yet vegetated. The step pools and tailout areas easily handled heavy flow from both snow melt and rain, demonstrating both the added capacity and erosion protection that the stream restoration features provide.

With the remnants of the historic snow storm downstream, the restoration contractor was able to return to work in Klingle Creek. Recent work includes step pool, stone toe (stream bank armoring), and fabric encapsulated soil lift construction.

The contractor also completed a riffle grade control feature, which mimics the naturally-occurring flat areas in streams where the water flows over a mix of river rock and small boulders.

The contractor also started work on clay channel blocks, which span the width of the stream channel and extend 4-5 feet into the earth.  Clay is the most dense of all naturally-occurring soil materials, and when well compacted it forms a water tight barrier. The groundwater level in the upper reach of Klingle Creek is high, and these clay blocks will reduce the amount of groundwater that bypasses the stream channel.

A DDOT inspector tests the density of the compacted clay in the channel block.

Meanwhile, the new retaining wall across from the Woodley Park Towers is nearing completion.  The salvaged stone finish is taking shape!

 A mason applies mortar between salvaged stones.

Progress Update - Week Ending December 11, 2015

Stream restoration work has been the priority activity on the project for the past two weeks, with the stream restoration contractor, Environmental Quality Resources, focusing on Segment 4 east of Connecticut Avenue.

Stream restoration work for the past two weeks focused on Segment 4, east of Connecticut Ave.

The contractor started Segment 4 work by establishing the new stream banks. This was achieved by excavating the existing banks and installing large stones cut roughly into blocks.  The blocks (called "imbricated riprap") are stacked in such a way to armor the stream bank and greatly reduce erosion.

On the opposite bank, EQR started installation of fabric encapsulated soil lifts.  These soil lifts will be vegetated and will absorb overflow during flood events when complete.

Once the stream banks are built up, the contractor will then install step pools within the stream.  Step pools greatly reduce stream flow and erosion by temporarily pooling water before it cascades to the next lower pool. Segment 4 will have 15 step pools when complete.  EQR installed the first step pool boulder cluster last week.  Boulders for step pool clusters are carefully selected to ensure a watertight fit.

The westernmost step pool boulder cluster in Segment 4 was set last week.

Overhead schematic of a step pool.

Finally, the contractor removed two Ash trees along Klingle Road that will soon succumb to the Emerald Ash Borer (EAB) epidemic. Given the trees' size and position hanging over Klingle Road, the trees had to be removed for safety purposes. Click here for more information from DDOT regarding Ash trees and the EAB.

Crews remove an Ash tree along Klingle Road.

Crews remove an Ash tree along Klingle Road.

Progress Update - Week Ending November 27, 2015

It's been a busy couple of weeks on the Klingle Valley Trail! Stream restoration and retaining wall construction are underway, gas line relocation work continues, and the east entrance to the jobsite is now open for construction traffic.

After two weeks of site preparation and materials deliveries, the stream restoration contractor started work on Segments 2 and 3, shown on the image below. 

KVT stream restoration segments.

Stream restoration construction is difficult work.  The contractor has to dam up the upstream side of the creek and divert the water flow using a pump and hose system. Once the work area is sufficiently dry, the contractor then excavates the stream bed to provide a stable foundation for the restoration features.  In this case, the contractor installed a Stone Toe, which consists of stacked boulders that will prevent future erosion along the stream banks. The stones come from the quarry roughly cut into block shape (called "imbricated riprap"), and must be placed at precise locations and elevations based on the design stream channel levels. 

Additional stream restoration site preparation activities took place last week, including access point grading and tree removals. Some of the trees that were removed to accommodate the new stream channel were saved with root wads in tact to be reused in the restored stream. The root structure when placed in the stream creates new habitat for aquatic life. 

The prime contractor started work on the first new retaining wall on the project. The wall is near the west end of the trail just behind the Woodley Park Towers building. The wall replaces a stone masonry wall that collapsed many years ago. The wall will serve as one of the banks of Klingle Creek, so the contractor had to take similar steps to dewater the area each day using pumps. With all pump-around activity on the project, the pumps must be turned off by 7 PM to minimize noise disturbance.

The concrete foundation for the retaining wall was installed on Monday, November 23rd. 

To maintain the historic character of Klingle Road, the project will reuse much of the existing stone from the area. For the retaining wall, we are salvaging stone from the existing stone walls that collapsed into the creek. 

The contractor also stabilized the east entrance of the job site, near the Porter Street interchange.  The east entrance is now accessible to construction traffic and will prevent any backups at the west entrance, where Washington Gas continues to work along both Klingle Road and Cortland Place. Look for a new retaining wall to be built along this slope in 2016.

Washington Gas continues its work on the west end of the project. Phase 1 is nearly complete, with 300 feet of pipe left to be installed, and Phase 4 continues along Cortland Place towards Devonshire Place.

Progress Update - Week Ending August 21, 2015

Washington Gas Phase 1 line replacement continued this week, moving west of Connecticut Avenue and away from the difficult subsurface conditions below the bridge.  

On Monday, Washington Gas fabricated a 90-degree pipe section and tied it into the existing gas line with a valve just to the east of the Connecticut Avenue Bridge. A permanent valve was installed along the new gas line on Tuesday, which was then backfilled and topped with asphalt.  The asphalt is a temporary erosion control measure and will be removed during trail construction.

Existing utility lines and stormwater pipes are always a challenge in urban construction, and Klingle Road is no exception. Washington Gas encountered four separate pipes in its trench path this week:  a terracotta drain pipe from the Connecticut Avenue Bridge, an abandoned steel gas pipe, a concrete sanitary sewer pipe, and another lateral storm drain pipe. Excavating around these existing lines is delicate and difficult work.

Excavation under the Connecticut Avenue Bridge revealed four separate utility and drainage pipes

As the pipe crew progressed away from the bridge, the gas line trench was outside the Klingle Road footprint.  Since pavement breaking was not needed, Washington Gas was able to excavate 75 linear feet of trench on Thrusday and Friday.