After a long season of preparations, work finally begins at the old mill pond on Rout 13 in Crapaud. This pond is an important historical and environment site and has housed lumber mills and a killen. Over the years it has passed through numerous owners and has gone by the name of “Stordy’s” “Steward’s” and “Sherren’s” ponds.
Although beautiful, the spillway has been an issue for fish passage, with no passage in over 50 years, leaving the fish populations located above the dam isolated. Any fish which do decide the leave the River for the estuary have no way of returning, resulting in poor genetic diversity in the fish and limiting population growth, as without other species of fish, the only available fish food source for the trout are their own young or the young of other trout.. This dam is located at the head of tide, blocking the entire East branch of the Westmoreland River.
Planning for this project began last season, with an engineering assessment of the spillway. It was determined that the spillway was undermining itself and was of questionable integrity. The more recent occurrence of flash floods would inevitably result in a breach of the dam, putting the river below and the estuary at high risk for an environmental disaster. The local watershed group had to decide to either do a controlled demolition of the dam reverting back to an unimpeded river, or devise a plan to repair the spillway and restore passage to the fish. It was decided to attempt to protect the pond, as it has both historical and emotional value to the community
The first thing we did, was ensure that if we did fix fish passage into the pond, that they could actually get from the estuary to the upper river. Our summer student did a culvert assessment to ensure there was no other important blockages, one such blockage was the crush culverts which were fixed earlier this season and replaced with a free span bridge.
Prior to this project the Department of Transportation and Infrastructure Renewal replaced the Culvert on Route 13 with the concrete arch and natural bottomed passage seen below. The old bridge had suffered fire damage and was deemed unusable.
The first step at the pond site was degrubbing. That’s when your remove all debris which will be in the way of the structure. Type 1 sediment fence was placed along the river to isolate it from any work sites. Luckily most trees which had to be removed where scrub trees, —Alder, Willow, and wild cherry which will be replaced with more suitable trees during project completion.
There was a lot of dirt to be moved. The site was excavated to a < 3% slope between the proposed inlet to the fish ladder and outlet to the river below
The shale was kept on site, used to build the base for our new parking lot, and used to raise the existing berm 18 inches and widen it to allow for heavy equipment to access the spillway for the repair phase of the project to take place next season.
Type 1 sediment fence was once again installed around all sides of work sites. During the 2014 spring freshet, water was passing over the dam, luck of rainfall amounts was the only thing which kept the berm form breaching. The raised berm will better protect the river from flash floods in the future
The berm was widened and secured to allow for heavy equipment placement of the draw down structure and the spillway repair next season. The spillway will have large rock placed and secured by the addition of concrete. This can not occur until after the fish ladder has been installed as we will be using the ladder to reroute the river allowing us to install the draw down and do the spill-way repair in the dry.
The ladder was excavated to <3% slope, this was harder than one would think, and took constant surveying to ensure it was accurate. Water is very unforgiving, if the slope isn’t right the water will find its appropriate path. Once correct, geofabric was placed as a base for the ladder. We did have great luck, the fish ladder required excavation down to bedrock, this made for difficult digging, but will help ensure the ladder wont erode or leak.
a combination of rip rap, fish gravel and large rock (not yet in these photos) are placed to ensure appropriate habitat within the fish ladder and adequate resting places for the fish as they traverse the ladder. We hope that within a few years, the natural bottomed fish ladder will incorporate itself as a natural looking part of the river (ok, natural for NB as we don’t have granite, but we wont tell the fish). Shrubs will be added as cover for the fish, artificial cover will be added to act in the interm.
This is the completed excavation of the fish-way. A 2 ‘ culvert was placed at the head to control water coming into the ladder. Once the blockage is removed in the spring, a constant flow of water will be supplied to the fish-way no matter the height of water in the pond.
The old access road to the dam will become a private maintenance road and will be gated. This road opened onto route 13 in the hollow on the curve and was not suitable for public access do to safety concerns. A new public access and parking lot will be installed off route 13 opening to the side of the park.
This access road was an major hurtle to over come. First we were going to maintain our <3% slope up the entire ladder and have a bridge going over to supply access. This was very costly and was abandoned for the much cheaper culvert plan. Department of Fisheries didn’t want the culvert sloped, as it was thought this would actually impede fish passage. It was decided to redo the blueprints and place the culvert level (in comes the surveyor). Next problem was to ensure the culvert would be maintained full of water. Placing a level culvert in a sloped system would cause the water to be deep on the upper end and too shallow for fish passage on the outlet. The solution was the addition of baffles, to create a pool below the culvert backing the water up through the culvert.
This is placement of the baffle below the lower culvert, one was also placed below the inlet culvert.
the pool was covered with fabric and rock, the baffle was designed to ensure the appropriate amount of water would flow into the fish-way below the pool. The baffles were placed to ensure they were level and at the proper height so the water will flow out the baffle and not route around. This project required almost constant surveying.
The new access road is complete, the site was routinely covered with straw as during this construction found ourselves under constant treat of heavy rains. May thanks goes out to our watershed volunteers who monitored the site for weather related issues and reported as required, and supplied many of these photos
It’s been a busy fall working at the pond, but the project is ready to be put away for the winter.
The photo below shows the completed natural bottomed fish passage ready to be opened to traffic in the spring.
This is the upper section of the passage from the culvert under the improved access road on the left, up to the pond access culvert on the right. At the moment the water is blocked with plywood and sandbags. in the spring this culvert will control the amount of water entering the ladder. This photo is being taken at the sign location in the new parking lot and also shows the completed new and improved berm around the bottom of the pond.
The last task of the season was the addition of coconut fiber matting. This project was too late in the season to anticipate root growth from seeding. During the installation process the site was covered with lots of straw and survived through numerous rain fall events without damage. We expected we would need something more substantial for winter protection as there is a lot of exposed sloped land, the fiber matting was an good solution.
We had planned on opening the fish ladder last week, but was dependent on the scheduling of equipment. Matt installed the cap over the end of the inlet culvert, this will limit the amount of water entering the culvert. Water flow rates will be measured to determine if a rock berm will need to be placed in from of the culvert to slow flow.
Above =inlet culvert with cap
Looks nice with all the snow gone. The fish ladder came through a rough winter with very little movement of soil
We received short notice Monday morning that today was the day.
A load of R250 granit was delivered and placed at the out flow
Cloth was placed over the culvert to limit the sediment movement. The two willow stumps were removed and a channel formed to the inlet culvert
First water heading though the inlet culvert. The was a bit of sediment from the opening and pipe, but it all cleared within a few minutes
Here she comes :)
Water is all clear. We will be taking some flow rates in the ladder and adjusting rocks as required to optimize fish passage
Now the question is, Does it work?
Matt Persuades a few waiting volunteers to try it out
The Smelt were placed gently behind a rock in the last run, a few were quickly swept downstream, but quite a few settled in behind the rock or along the sides of the ladder. We will be checking on their progress up the ladder
It’s nice to see this phase of the project coming to a close, Many thanks goes out to all our partners
Recreational Fisheries Conservation Partnership Program
Prince Edward Island Wildlife Conservation Fund
Prince Edward Island Department of Environment, Labour and Justice
Prince Edward Island Department of Agriculture and Forestry
Tryon River Watershed Cooperative
Prince Edward Island Department of Agriculture and Forestry
South Shore Watershed Association
Jobs for Youth Program
Canada Summer Jobs
Prince Edward Island Greening Spaces Program
First hurdle for the fish is to find the entrance to the fish ladder from the river, and be able to make it up the swift water into the fish ladder — the fish are heading up stream, so the water leaving the fish ladder is actually the ” entrance” So step #1 : will they find and enter the ladder? Answer : Yes
I did expect the smelt to find, and enter the ladder, but expected the access road culvert to be an impassable blockage. They would have to go through a small opening in the culvert weir in order to access the pool below the culvert Step #2: Can they make it up into the road access culvert pool, through the baffle ? Answer: YES
Culverts can cause fish blockages due to the velocity of the water, and lack of rest stops in the culvert. Step #3 : Can they make it through the road access culvert? Answer: YES!
close up of fish on inlet side of the access culvert
OK, so they have already gone further than I thought they would :) Step #4: can they reach the top Answer: YES!!
Now the big question! Can they navigate the inlet culvert and reach the pond? ???????Jonathan Platts (ducks unlimited) took water velocity readings to see if this was likely, these looked very favorable The smelt were netted to determine sex variance — 76% male — so the girls can make it through too :) But unfortunately, the ones who made it through into the pond didn’t wait for their photo op. :( Sean Landsman (UPEI Phd ) is setting up antenna to monitor the fish passage. He will be tagging some smelt and documenting their progression through the ladder ——————————— Stay tuned ;)
Yesterday I got the great opportunity to witness smelt tagging! Connor and I just happened to be doing our weekly water testing below the pond when we were invited to watch Sean (a UPEI PhD) student start tagging the smelt to see if they were able to make it into the pond via the new fish ladder.
I’ll be honest, I had no idea what tagging involved, so it was wonderful to witness it first hand! They had a ruler, a scale, the microchips (which were bigger than I expected), and a computer which recorded the chip ID# and the information about that fish (sex, length, weight)
A small incision was made in the belly of each fish with a large gauge syringe, and the microchip was implanted. The little hole would close immediately, causing no damage to the little smelt.
A total of 100 smelt were tagged and released back into the stream. The largest one they tagged was a female who hadn’t laid her eggs yet, she was beautiful!
She was almost 20cm long and just over 51 grams!
Several antennas are set up along the fish ladder to record the microchip information whenever the smelt cross them. The implanted microchips are not battery powered (which is healthier for the fish), so there will hopefully be readings for years to come!
Boom all ready to go – new toy makes for some great shots
Fill is going in for the coffer dam, patches are holding nicely :)
boom is holding well – no coloration going down stream
HINT – if you double click on the aerial shots they will blow up for you
Nice fish ladder
not so nice spillway
the spill way is pretty dry , hoping to have it all fixed this year – If the draw down go in on budget
After 85 loads of shale and hours of de-watering I have a very mucky hole, things are progressing nicely :)
what a beautiful site – coffer dam and boom are holding nicely and are at the designated elevation- we are right on track and on budget
I’ve been doing this too long to know that its not safe to relax when things are going well– sometimes I hate being right. :P
For those of you who don’t work around water and muck on a daily basis (I know your out there, I can spot you in a crowd -its the painted toe nails ), let me give you some schooling
your first lesson in “Dam 101”
When building a coffer dam, it’s not really a dam until you pump the water out from one side; until then it’s actually just a road across water, nice and stable being supported by the water on either side. When we removed the water (over 30,000 gallons or 300,000 lbs (calculated using the pumping capacity of my pump and length of time it took to empty the basin – need something to do to keep me awake at 3 AM) I was very happy to see our coffer dam withheld the change in forces nicely
second lesson in “Dam 101”
Water is essentially incompressible, therefore pond muck which is watery slime– is incompressible. If the slime was confined in a space it would support a lot of weight as long as the was a large enough surface area that you don’t sink.
once we had the basin dry of water, we had to dig it out to reach the elevation for our cement base.
when we removed some of the muck, the remaining muck settled to occupy the hole. In other words we took the side out of our confined container, the base of the coffer dam settled and the weight of the water on one side pushed in.
After a few moments of excitement and some expert machine handling by Tim, disaster was avoided, the coffer dam was re-stabilized.
Above and below is the now stable coffer dam
dam above is stable, but it was decided that continuing to remove more of the muck would risk destabilization.
Time to call in Brian for a consult
The solution to the muck situation :
we now have a coffer dam for the pond water and a coffer dam for the muck, allowing us to dig a stable hole to the appropriate depth for the cement base of the structure.
That sounds simple, but it wasn’t as easy as you would think.
Brian (that’s Brian McCullough our engineer) had to come from Nova Scotia to amend the blueprint allowing us to move the structure into a more stable work area. Tim (my trusty hymac operator from Matheson Construction) had to build another berm, re-dig the hole until he found stable ground, then bring it back up to the required level. I had to worry, take pictures and crunch numbers
Of course there are others on this team:
here’s Tim and Alan McLellan (Department of wildlife) Alan is surveying the base of the hole to ensure it is at the appropriate elevation and is level. Tim had to pack and level 9 loads of rock to get an appropriate base for the concrete (August 25th)
The McGuirk Bros. Construction crew putting in the forms and rebar for the base. The tower of the draw-down water height control structure will be sitting on the square section with retaining walls extending to either side. The base is 30 feet long and has rebar steel to reinforce the concrete. Each rebar rod was suspended in place with wire to ensure it would not extend past the concrete in any direction where it would be susceptible to rust. The water at the back is a drainage basin so we can pump the water out of all the rock (August 26th)
and of course Myles Lord – my ever willing side kick – has been pumping the water which pools between the two coffer dams into the lower section and then pumping out the work site. This water is from seepage and is expected and has been quite predicable to control with pump 2 – 4 times a day
Above – August 26th 5Pm pumping time at the work site – the cement has been in for hours, we will be back at 11 Pm for a final pumping of the day to ensue the rock under the concrete remains dry for as long as possible
All is going well :)
and then it rained !!!!!!!
No work being done here this morning
It’s Thursday August 27th – Myles and I pumped from 3- 5:30 AM and ran home for a nap, we’re now back on site at 7 am – so far things don’t look so bad. The site is wet and mucky but we’re between rain storms at the moment.
One concerning thing, is if the water raises too quick and comes over the coffer dam. I’ll be monitoring the situation and have authorized Roger (Matheson Construction) to install sand bags along the dam as per Brian’s recommendation.
I’ll be watching the “little Islands” out by the coffer to determine the change in water height. Myles is pumping the basins, especially the top one to ensure the lower coffer dam doesn’t get too mucky and unstable.
I monitor, worry and probably drive people nuts. Alan comes out to check on things and offer some suggestions, Myles goes to get me another pump……. wait a minute .. look up… where are my islands !!!!…. they’re gone !!!
Luckily .. I have a good team for support, weak spots in the dam were reinforced with sandbags. Alan calculated that the spillway had lots more capacity to handle water and Roger gave me a new worry stick. as long as the water is below the tape I’m good
By 4:30 the rain had passed, the sun was out. I suspect the water will continue to raise for at least 3 hours do to over capacity of the tributaries and run off from the land.
Above- by the time we came back to pump out at 8 pm my worry stick was high and dry :)
according to environment Canada we received 55mm of rain
The concrete pad is all cured, rebar is extending out through the concrete and will be embedded into the walls holding the structure together. The first of three culverts has be placed and packed with class A gravel to ensure it will remade stable and level while the forms for the walls go up and the concrete is poured
The culvert is supported on the wall rebar and placed at an angle to the draw down structure to maintain the appropriate distance from the spillway of the river
Next the forms for the walls go up
the second culvert is attached to the first and stabilized with class A gravel. A cut off wall is installed around the second culvert which will prevent water tracking along the culvert and washing them out
The forms are almost ready. Two of the three culverts have been installed and the cut off wall is installed and buried, we just dropped in for a site check and to pump out the water. It hasn’t rained, but we either have seepage, hit a spring, or both, the water shows back in upper and lower catch basins consistently and has to be pumped out every few hours…..yes arggg.. around the clock :(
That leads to the question??— the work site is small and surrounded by water– the spillway on one side, pond in front and fish ladder on the other– guess it’s not so surprising a hole in the middle keeps filling with water! so, What are we doing with all the water?? at first, when there wasn’t so much exposed soil, we were pumping the water out of the hole, through the grass and behind a double layer of silt fencing. The water from the hole is surprisingly clean and this was very successful. Once the culverts started being placed, there was a lot of exposed soil, any water pumped onto this would only wash soil into the river, so we began pumping it though the culvert and into the spillway.
fish ladder is all clean :)
there is some water discoloration in the spillway, which is mostly dry for the summer, unless we get heavy rains, the discoloration is actually from sediment in the spillway being stirred up by the water, the pumped water is quite clean :)
Where are we at now?
the third culvert has been placed, covered with shale and armored with plan B rock over filter fabric.
The rebar is being added to the forms
here comes the concrete— we had two cement trucks come and pour it into a BIG pump,
It’s Friday Sept 4th, the concrete is all set up– time to take the forms off. The concrete will be left to harden for the weekend. Tuesday we will begin packing the shale around the structure
nice view :)