Construction is Done

This week was spent driving willow stakes in strategic locations, cleaning up, and moving out. The photo above shows willow stakes planted through the coir fabric on the bank next to the 5th bridge.  These stakes will sprout and provide both screening and bank stabilization.  We weren't able to plant nearly as many of these as we would have liked.  But we were able to get them into certain key spots, like adjacent to the bridges and the boulder bank treatments.  The photo below shows the construction foreman loading up creosote-treated logs, some of the last of the construction debris.

Before the contractor left, all areas impacted by construction were restored to their pre-construction state.  The photo above shows one of Bubalo's crew hand-finishing an area that had been used for heavy equipment access.  

The photo below shows the 3rd bridge.  The construction is complete, but the restoration is not.  Nature Center staff and volunteers have started planting native plants along the stream.  Between the construction, the planting, and time, the project team is confident that we are creating a healthy riparian corridor. Birds and fish have already started returning to the stream and the trails will be open to the public starting next week.

Opening Up the Weir

A small crowd of Habitat Stewards and Nature Center staff began to gather at about 1 this afternoon to watch the dam being removed at the north lake.

Using a combination of heavy equipment and hand labor, the sandbag dam that had been keeping the north lake from flowing into the stream was removed.

The dam at the south lake had already been removed and the fall is so short between the two lakes that the stream had backed up all the way to the dam at the north lake.  This made the breaching of the weir rather anticlimactic, but it was still terrific to hear the water babbling over the weir again. 

Once the dam was removed, the contractor finished the boulder treatment of the west bank, placing a large boulder in the place where the dam had been.  The crowd of onlookers was very impressed by the contractor's teamwork and delicate touch with the back hoe.

This is what the weir and the 1st bridge look like now.  In case you don't remember or didn't ever see it, below is what the weir looked like at the start of this project.  The first photo is looking downstream from the 1st bridge, the second photo is looking east across the weir.

Bioengineering

One of the last pieces of the stream restoration is protecting the banks from future erosion. Due to the severely limited project budget, only the bare minimum of bioengineering techniques are being used. These photos show coir blankets being installed on the banks. Coir is a very strong and flexible mesh made of coconut fibers. It is being attached to the banks using wooden stakes and biodegradable staples (made from corn).  Plants will be planted directly through the blanket and the coir will hold the banks until the plants grow large enough so that their roots can form a strong protective matrix. Coir installation is labor intensive, and the Conservation Corps of Long Beach (in the blue shirts) was brought in to assist. This provided good work experience for the Corps members and saved a little money for the project.

Coir blankets were installed along the full length of the stream (except at the boulder treatments and bridges).  Unfortunately, the project budget can only afford to pay for Bubalo to plant willow stakes at key locations.  Over the next few months, Nature Center staff and volunteers will be planting container plants and more willows to provide additional bank protection, riparian habitat, and visual screening.

Some EDNC regulars just can't wait

This pair of ducks was enjoying the area just upstream of  the 3rd bridge this morning.

Apparently, they decided to head north.

Good thinking (for a duck), as the stream was about to disappear...again.

Off they went towards the north lake.

They'll be able to swim all the way from one lake to the other soon -- just not quite yet.

The bridges are in.

The bridges have all been installed and the trails approaching them have been regraded to provide smooth transitions. In some places, ramps were constructed to bring the level of the trail up to the level of the bridge. Boulders were placed on the sides of the ramps to provide stability and aesthetic appeal. The photo below shows the 1st bridge, where the stream flows out of the north lake.

In addition to creating a smooth transition between bridge and trail, the areas around the bridges were graded to direct runoff from the trails into vegetation, rather than having water flow onto the bridges or straight down the stream banks. This helps prevent erosion and creates a more pleasant walking experience in wet weather. The photo below shows bridge 2.

Below is bridge 3. In front of the bridge is a roll of coir fabric that will be unrolled and tacked to the bank next week.  Behind the bridge, you can see the alder that was felled earlier in the week.  You can see how close this alder is to the bridge and what a hazard it was to have a large standing dead tree so close to the trail and bridge.

The photo below shows the 4th bridge, near the junction of the 1-mile and the 2-mile trails. The point bar, which is not quite finished, can be seen in the background.

Here is the 5th bridge. The high water mark on the banks is a dramatic illustration of just how much water was in the stream from the recent storms.

Residents and visitors to the Nature Center began using the bridges as soon as they were installed, as evidenced by these prints on the 4th bridge.  I assume the boot print is from one of the construction workers.  This bridge was installed last Friday (2/5) and this photo was taken on Monday (2/8).

T..I..M..B..E..R..!..!..!

The bridge abutments are finished and the bridges are being installed.  The photo above shows where the 3rd bridge will be (the bridge itself is sort of visible on the west bank).  Just at the bend in the stream, you can see a large double-trunked alder.  What you can't see in this photo is that the tree is tall, dead, and rotting.  The project team was concerned that it could fall on the brand new bridge, something that would be both dangerous and expensive.  So we decided to take it down and make it a feature instead of a liability.

The contractor first dug a large hole behind the tree so the root ball could come out more easily.

Then the contractor just pushed the tree over.  This was not as simple as it looks -- it takes skill to aim a tree trunk with a back hoe.

After a bit of pushing, digging, repositioning, and pushing some more, the tree finally came down.

There is a good amount of water in the stream from last week's rains and the tree made a tremendous splash when it fell.

The tree fell exactly where the project team wanted it.  To eliminate the temptation to cross the stream on this ad hoc bridge, the branches and upper trunks will be cut and hauled up into the blackberry thicket on the far side of the stream.  The root wad and lower trunks will stay pretty much where they are, creating an interesting little spot in the stream.  This is right next to Bridge 3, so visitors will have an excellent view of it once the trail is reopened.  Be sure to look for it when you're here.

Bridges!

The streambed was dry enough this week to backfill around all the bridge abutments and do almost all of the finish grading.

Many of the bridge approaches had eroded so severely that the trails approaching the bridges had to be raised a foot or more. The photo below shows the upstream approach to the 3rd bridge, an area that was chronically muddy and where the trail was crumbling into the stream.  The regraded trail looks perfectly normal in this view. 

But look at that same stretch of trail viewed from just downstream of the bridge in the photo below.  Notice the trail marker and bench next to the bridge abutment--the bench is now below the level of the finish grade.  Obviously, the bench will be removed and the area filled to bring the grade up to match the surroundings.

The biggest excitement this week was the arrival of the bridges from Alabama.  They arrived very early Thursday morning and were off-loaded to the staging area near the utility towers.

The photo below shows the 5th bridge (the one closest to the south lake) being placed. Once the exact location for the bridge was determined, the contractor marked the places to drill and began the process of bolting the bridge to the abutment and making sure it was level. By the time rain stopped work on Friday, the 5th and the 4th bridges were done.