Tuesday, August 30, 2011
boulders are emerging as the river below
Rhodes-on-the-Pawtuxet lowers to its new levels.
At high tide last Friday evening, the natural
flows and sounds of the river, no longer tethered
by its old spillway, were a wonderful validation
of this restoration project.
Looking through the Broad Street bridge and
across Pawtuxet Cove at high tide, the
connection between river and bay now
Friday, August 26, 2011
In advance of this weekend's storm, the Sumco crew is working feverishly, both chipping away at the remaining concrete and removing the debris from the site. The project team has been in communication with RIEMA and the municipalities, providing assurances that, by the end of Friday, all equipment and debris will be out of the river.
The final photo in this series taken Thursday evening at high tide shows the free flowing river and the best evidence yet of the potential for successful passage between river and the bay - for fish and paddlers!
Wednesday, August 24, 2011
Tuesday, August 23, 2011
Today Dick Quinn from US Fish & Wildlife was on site, working with Curt Mason of EA Engineers to cut a low-flow channel in the river bed along the south bank of the river. Its purpose is to ensure that even if river flows are unusually low during the spring fish run period, shad and herring will be able to swim upstream over the restored Falls. Flows were relatively low today and we took advantage of low tide in the morning. The first photo shows Dick at work with Arthur, one of the guys from
Monday, August 22, 2011
Conditions look good this week, with relatively low flows and low tide during the day. SumCo spent the morning pulling back rubble left from demolition of the center spillway, and is now back at work continuing the demolition of the south spillway. This section of the dam is much more massive than the last; its demolition should take the better part of the week--if we don't get any rain and flows stay low. Following the demolition, SumCo will remove all concrete rubble from the river, filling steel containers to be hauled out by crane. Here's what it looks like now. The orange turbidity curtain is in place to prevent concrete dust from the demolition from moving downstream with the current.
The project has received much attention in the media lately. On Friday evening channel 10 (WJAR) covered the project.
EcoRI has also covered the project. Click here to read the article.
And if you haven't had the chance yet, be sure to get down to the river check out the dam destruction for yourself!
Wednesday, August 17, 2011
If you compare this with the videos from last week, you'll see that as the dam removal got underway, the river was flowing over the bedrock and through the slot in the south spillway. Now it has risen to the point where it is again flowing over the north and south spillways. Hopefully it'll be down enough by tomorrow that SumCo can get back in the water.
You can check out the river's flow in real time, courtesy of USGS, by clicking here
This project on the Pawtuxet River has been a good lesson in watershed hydrology. As the work crew was at the site on Monday, preparing water control for removal of the last section of dam, rain was falling steadily and water levels rose as they were working. It became clear by the middle of the day that there would be no more work in the river until water levels fell.
Looking at this hydrograph from the USGS gage in Cranston, you can see the flashy nature of this river system and how it responds to rain events. The first rain event we had on Sunday, August 7th, rose water levels to over 800 cfs. Flows were also being manipulated by a hydro operation upstream. The several inches of rain we had on Monday were enough to increase flow from under 200 cfs to over 1,000 cfs within a few hours. Because the watershed is so large, flows have still not dropped substantially two days later. Some of this is due to the fact that the Scituate reservoir is now full and is spilling over its dam. Flows on Monday were the highest for that day since August 15th 1973 when a flow of 827 cfs was recorded at the Cranston gage.
Rivers respond to what is happening in the watershed. A large amount of impervious surface causes quick rises in river flow. Manipulation from dams and other human influences also cause flow fluctuations putting added stress on the river's ecology and built environment. When flows reach around 500 cfs, we will see the crew back at work on the last section of dam.
Tuesday, August 16, 2011
On the evening of August 10th, Alan Libby from DEM's Fish & Wildlife Division, took his team of four for a trip up river from the Pawtuxet Falls dam to assess the prevalence and variety of fish currently in the river. For the 2 mile section that they examined, they found the following in order of abundance: white sucker, golden shiner, American eel, brown bullhead, pumpkinseed, common carp, yellow bullhead, bluegill, and largemouth bass. By far the most prevalent fish was the white sucker. All fish caught during the sampling appeared healthy according to the team, and are also found in other parts of the Pawtuxet system. No anadromous fish were found, however, including the herring and shad that are target species of this project.
Such testing of the lower Pawtuxet has not been done since the late 90s. With the work completed last week, we now have a baseline for evaluating the primary impact of the dam removal. DEM will continue to conduct annual assessments to measure the degree and rate of restoration of anadromous fish to this river. If resources permit, some stocking of the Lower Pawtuxet will take place to help accelerate the process.
Friday, August 12, 2011
Wednesday, August 10, 2011
With the recent rains, the flow of the Pawtuxet River is much higher than anticipated, and construction crews are working to lower water levels as they begin to remove the dam. Two notches were carved out of the dam on Tuesday and Wednesday, and sandbags and steel plates are being used to control water levels. The river will not be drawn down more than 6 inches a day. In a few days, we should see more of the dam exposed. In these photos from today, you can see the hydraulic hammer working on the northern portion of the dam. A notch was cut in the southern part of the dam on Tuesday.