November 2006
IT’S DREDGING TIME AGAIN AT SHOLLENBERGER
Shollenberger has been a dredge spoils site since the 1970s. Once again the site is fulfilling its thirty-year role, helping to maintain navigability of the Petaluma River by being a depository for the dredge spoils removed from the river.
This year’s dredging is taking place at the downtown Turning Basin, followed by the stretch of river between the D Street bridge and McNear Channel. If time and money permit, the Petaluma Marina will also be dredged again. The work should be done before the first of December. It is expected that some 35,000 cubic yards of silt will be piped into Shollenberger at a cost of $1.6 million, almost entirely paid for by the state, supplemented by money from FEMA.
Soon after the work started, muddy water could be seen entering the park near the northwest corner of Shollenberger. Some people expressed concern that this would have a negative impact upon the wildlife. Actually, if this dredging is similar to the dredgings of the past few years, the muddy river water will contain an abundance of food for the birds: invertebrates and even small fishes.
September 23, 2005
The dredging of the Petaluma Marina has finished. The Harbor Master's Office says the project's goals were met. The pipes will be removed from the park shortly.
The dredging of the Petaluma Marina has finished. The Harbor Master's Office says the project's goals were met. The pipes will be removed from the park shortly.
I now estimate water and dredge spoils may have increased the depth of the central pond by 12"-18". There currently is a small amount of water entering the left freshwater channel through the weirs but that shouldn't last long. In the northern part of the pond the water is viscous from the introduced sediment. The sediment will eventually settle on the pond bottom with the winter rains covering much of it.
August 22, 2005
The dredging of the Petaluma Marina is ahead of schedule, per Bob Pedoncelli, an engineering consultant with the City. Bob checked the weirs at the end of the left freshwater channel today. He says the pond's water level has risen about six inches since the dredging started. It would have to rise another 12" before the brackish water would "decant" into the channel and he says that is unlikely as the dredging is half over. Since the pond has a flat bottom, the six inch increase is quite noticeable. Large numbers of egrets and other birds are harvesting fish in the early mornings as the dredge waters are rich in nutrients.
The dredging of the Petaluma Marina is ahead of schedule, per Bob Pedoncelli, an engineering consultant with the City. Bob checked the weirs at the end of the left freshwater channel today. He says the pond's water level has risen about six inches since the dredging started. It would have to rise another 12" before the brackish water would "decant" into the channel and he says that is unlikely as the dredging is half over. Since the pond has a flat bottom, the six inch increase is quite noticeable. Large numbers of egrets and other birds are harvesting fish in the early mornings as the dredge waters are rich in nutrients.
August 5, 2005
Dredging of the Petaluma Marina into the Shollenberger dredge spoils site is now underway. The water is moving through the dredge pipe in a steady stream and there are already standing pools of water.
Dredging of the Petaluma Marina into the Shollenberger dredge spoils site is now underway. The water is moving through the dredge pipe in a steady stream and there are already standing pools of water.
AUGUST 1, 2005
Dredging of the Petaluma Marina is scheduled to start any day now. It will be done under a contract between the City of Petaluma and Eagle North America. Boats will be moved around the marina to accommodate the work which may take upwards of two months to complete. The spoils will be pumped one-half mile to Shollenberger Park. The pipe has already been lain across the trail at the northwest corner of the park. A dirt "ramp" has been fashioned on top of it so as not to inconvenience those using the trail. The dredging company estimates 37,000 cubic yards of spoils will be placed into the Shollenberger site, compared to the river dredging of 2002-03 which resulted in 250,000 cubic yards being introduced into the site.
Dredging of the Petaluma Marina is scheduled to start any day now. It will be done under a contract between the City of Petaluma and Eagle North America. Boats will be moved around the marina to accommodate the work which may take upwards of two months to complete. The spoils will be pumped one-half mile to Shollenberger Park. The pipe has already been lain across the trail at the northwest corner of the park. A dirt "ramp" has been fashioned on top of it so as not to inconvenience those using the trail. The dredging company estimates 37,000 cubic yards of spoils will be placed into the Shollenberger site, compared to the river dredging of 2002-03 which resulted in 250,000 cubic yards being introduced into the site.
October 9, 2003
The dredging of the Petaluma River is scheduled to be over by October 15th. When completed Nova Corp. will have removed over a quarter-million cubic yards of sediment from the river bottom, at a cost of $3.2 million paid by the federal government. The goal has been to widen the channel to 100 feet and to a depth of 9 feet. Dredging improves the navigability of the river and is an important flood reduction measure.
The dredge spoils, along with a lot of water have been dumped into Shollenberger as the location serves not only as a dredge spoils site but a popular park. Nutrients, including small fish, have been introduced into the park by the dredging and have attracted a lot of birds, including many American White Pelican.
There has been a problem with excessively salty water being introduced in the (otherwise) freshwater channels that are seen at the park entrance. The channels were fresh as late as August 16th, but when measured for salinity on September 28th, were almost 18ppt (parts per thousand) salt, considered highly saline. This level is quite high for some of the creatures that dwell there including the Western Pond Turtle, a species of concern in California because of dwindling numbers. I requested that the city reduce the amount of excess water coming into the weirs that control flow into the channels. The hope was, that artesian springs in the channels would reduce the waters salinity given a smaller inflow of the highly saline waters. The city agreed and reduced the flow on October first. The attached photo shows how a slotted wooden board has been placed across a weir (both weirs actually have this modification). Some holes were made under the board allowing a smaller flow. If the water rises about six inches or more, additional water will flow through the slotted hole into the channels.
A nice fall rain would also help ameliorate the salinity of the channels. Until then we hope the turtles and other delicate freshwater creatures will persevere.
The dredging of the Petaluma River is scheduled to be over by October 15th. When completed Nova Corp. will have removed over a quarter-million cubic yards of sediment from the river bottom, at a cost of $3.2 million paid by the federal government. The goal has been to widen the channel to 100 feet and to a depth of 9 feet. Dredging improves the navigability of the river and is an important flood reduction measure.
The dredge spoils, along with a lot of water have been dumped into Shollenberger as the location serves not only as a dredge spoils site but a popular park. Nutrients, including small fish, have been introduced into the park by the dredging and have attracted a lot of birds, including many American White Pelican.
There has been a problem with excessively salty water being introduced in the (otherwise) freshwater channels that are seen at the park entrance. The channels were fresh as late as August 16th, but when measured for salinity on September 28th, were almost 18ppt (parts per thousand) salt, considered highly saline. This level is quite high for some of the creatures that dwell there including the Western Pond Turtle, a species of concern in California because of dwindling numbers. I requested that the city reduce the amount of excess water coming into the weirs that control flow into the channels. The hope was, that artesian springs in the channels would reduce the waters salinity given a smaller inflow of the highly saline waters. The city agreed and reduced the flow on October first. The attached photo shows how a slotted wooden board has been placed across a weir (both weirs actually have this modification). Some holes were made under the board allowing a smaller flow. If the water rises about six inches or more, additional water will flow through the slotted hole into the channels.
A nice fall rain would also help ameliorate the salinity of the channels. Until then we hope the turtles and other delicate freshwater creatures will persevere.
SEPTEMBER 11, 2003
Dredging of the river south of the park continues. Jim Anderson, the Project Superintendent for NOVA Group estimates 20 more days will be needed absent further breakdowns. The level of the central pond is much higher than a month ago with the inflow sometimes sludge (see photo) or sometimes mostly clear water. Because of concern about failure of the 1500' dirt berm created last year to "protect the pickleweed", the Corps of Engineers told NOVA to remove the boards slotted against the weirs that block pond water from entering the freshwater side channels. The brackish waters are now rushing into the side channels. These waters flow through the channnels, and to Adobe Creek and then back to the river. This cannot have a positive impact on the freshwater life, including the rails and Western Pond Turtles, and I have questioned the amount of the inflow but it's tough to argue with the government. Meanwhile the rails have taken to the higher grounds in the cattails where I hear them "complaining".
Dredging of the river south of the park continues. Jim Anderson, the Project Superintendent for NOVA Group estimates 20 more days will be needed absent further breakdowns. The level of the central pond is much higher than a month ago with the inflow sometimes sludge (see photo) or sometimes mostly clear water. Because of concern about failure of the 1500' dirt berm created last year to "protect the pickleweed", the Corps of Engineers told NOVA to remove the boards slotted against the weirs that block pond water from entering the freshwater side channels. The brackish waters are now rushing into the side channels. These waters flow through the channnels, and to Adobe Creek and then back to the river. This cannot have a positive impact on the freshwater life, including the rails and Western Pond Turtles, and I have questioned the amount of the inflow but it's tough to argue with the government. Meanwhile the rails have taken to the higher grounds in the cattails where I hear them "complaining".
July 27, 2003
Dredging of the Petaluma River is scheduled to recommence this week. Nova Group will be completing the 2002 contract they have with the Corps of Engineers. Approximately 12,000 feet of the Petaluma River needs dredging south of Shollenberger Park to the lower dredge limits. Some work also is required at the Turning Basin which will be done with clam-shell equipment, weve been told. Heavy equipment has been brought into the park to strengthen the dirt berm required to isolate the western part of the park where pickleweed is growing from the dredge spoils and water that accompanies the spoils. Its possible the endangered Salt Marsh Harvest Mouse might reside in the pickleweed, although none has been seen so far. Although the winter dredging dumped more water than had been anticipated, its now obvious that nutrients ( likely small fish and invertebrates) were introduced in the process. Several migratory ducks that normally dont nest at the park did (one example being the Ruddy Duck), and there is currently a dozen or so Pied-billed Grebe fishing the central pond (more than seen for years). Recently, White Pelicans have also been doing well.
FEBRUARY 11, 2003
The dredging of the Petaluma River is over. Although the 1870 DRAGON's pump was repaired, National Fisheries declared the river off-limits because of fish migration. There has not actually been any dredging since the DRAGON broke-down at the Turning Basin in January. This was a troubled project from the onset and not all goals were accomplished. As far as the park is concerned, we have been doing water sampling in the left side channel and central pond since early December. Preliminary findings are that salinity in the left "freshwater" channel is decreasing as no dredge water has entered it for about a month. The water level is dropping also and the birds that prefer the channels are slowly reappearing, such as the American Bittern and Virginia Rail. The pond level is also slowly subsiding. Berms used by such species as the American Avocet and Black-necked Stilt for nesting are still underwater, however. We hope the berms will reappear in time! See the PETALUMA POST March and April issues for a full account of the dredging.
Dredging of the Petaluma River is scheduled to recommence this week. Nova Group will be completing the 2002 contract they have with the Corps of Engineers. Approximately 12,000 feet of the Petaluma River needs dredging south of Shollenberger Park to the lower dredge limits. Some work also is required at the Turning Basin which will be done with clam-shell equipment, weve been told. Heavy equipment has been brought into the park to strengthen the dirt berm required to isolate the western part of the park where pickleweed is growing from the dredge spoils and water that accompanies the spoils. Its possible the endangered Salt Marsh Harvest Mouse might reside in the pickleweed, although none has been seen so far. Although the winter dredging dumped more water than had been anticipated, its now obvious that nutrients ( likely small fish and invertebrates) were introduced in the process. Several migratory ducks that normally dont nest at the park did (one example being the Ruddy Duck), and there is currently a dozen or so Pied-billed Grebe fishing the central pond (more than seen for years). Recently, White Pelicans have also been doing well.
FEBRUARY 11, 2003
The dredging of the Petaluma River is over. Although the 1870 DRAGON's pump was repaired, National Fisheries declared the river off-limits because of fish migration. There has not actually been any dredging since the DRAGON broke-down at the Turning Basin in January. This was a troubled project from the onset and not all goals were accomplished. As far as the park is concerned, we have been doing water sampling in the left side channel and central pond since early December. Preliminary findings are that salinity in the left "freshwater" channel is decreasing as no dredge water has entered it for about a month. The water level is dropping also and the birds that prefer the channels are slowly reappearing, such as the American Bittern and Virginia Rail. The pond level is also slowly subsiding. Berms used by such species as the American Avocet and Black-necked Stilt for nesting are still underwater, however. We hope the berms will reappear in time! See the PETALUMA POST March and April issues for a full account of the dredging.
JANUARY 17
The dredger, "1870 Dragon" is anchored at the turning basin awaiting repair of a pump shaft - damaged by some large object, possibly a piece of concrete. The dredging operation should resume by Monday, January 20. There is about 100 feet left to dredge at the turning basin, then the operation moves back down river, past Shollenberger Park and the treatment ponds. I've been told dredging may continue for about three weeks.
The dredger, "1870 Dragon" is anchored at the turning basin awaiting repair of a pump shaft - damaged by some large object, possibly a piece of concrete. The dredging operation should resume by Monday, January 20. There is about 100 feet left to dredge at the turning basin, then the operation moves back down river, past Shollenberger Park and the treatment ponds. I've been told dredging may continue for about three weeks.
DECEMBER 20, 2002
Just when I think I understand "the rules" during this dredging season, one or more of the various agencies involved change them! Today, Nova removed the top board from each of the glory holes, so that any additional water in the central pond can now flow into the side channels. Several days ago, as reported below,they were contemplating adding additional boards. One of the earlier concerns was excess water flowing back through the channels and into Adobe Creek, disturbing salmon migration. Apparently, the salmon migration season is over, or federal officials have relented to a degree. I speculate that allowing more water to move into the side channels may help reduce the chances of a levee break. As to the effect of all the extra water flushing through the side channels on the wildlife there, from rail to mukrat, I can't venture to guess. Park docents will monitor, but the creatures (or their parents) apparently survived the process back in 1996. Compare the pictures below to the glory holes in November.
Just when I think I understand "the rules" during this dredging season, one or more of the various agencies involved change them! Today, Nova removed the top board from each of the glory holes, so that any additional water in the central pond can now flow into the side channels. Several days ago, as reported below,they were contemplating adding additional boards. One of the earlier concerns was excess water flowing back through the channels and into Adobe Creek, disturbing salmon migration. Apparently, the salmon migration season is over, or federal officials have relented to a degree. I speculate that allowing more water to move into the side channels may help reduce the chances of a levee break. As to the effect of all the extra water flushing through the side channels on the wildlife there, from rail to mukrat, I can't venture to guess. Park docents will monitor, but the creatures (or their parents) apparently survived the process back in 1996. Compare the pictures below to the glory holes in November.
DECEMBER 18, 2002
The dredging of the river is behind schedule and completion of this difficult project is now estimated for mid-January. Additional storage is needed at the park, so several more wooden boards will be added across the glory holes (please see illustration from November 15th update). It now appears the waterline may be allowed to rise to almost the top of the levee. Water is flowing into the side channels from beneath the slotted boards, and an effort will be made to block this, as Nova and the Corps of Engineers are trying to minimize the amount of water flowing into the side channels. Our heavy rains have further complicated the project.
NOVEMBER 27, 2002
Despite some delays because of kinking in the drainage pipe, Nova Group says they are on schedule, and still hope to complete the "Second Reach" south of Shollenberger Park some 11,000 feet by December.
The dredging of the river is behind schedule and completion of this difficult project is now estimated for mid-January. Additional storage is needed at the park, so several more wooden boards will be added across the glory holes (please see illustration from November 15th update). It now appears the waterline may be allowed to rise to almost the top of the levee. Water is flowing into the side channels from beneath the slotted boards, and an effort will be made to block this, as Nova and the Corps of Engineers are trying to minimize the amount of water flowing into the side channels. Our heavy rains have further complicated the project.
NOVEMBER 27, 2002
Despite some delays because of kinking in the drainage pipe, Nova Group says they are on schedule, and still hope to complete the "Second Reach" south of Shollenberger Park some 11,000 feet by December.
NOVEMBER 15, 2002
Wooden boards are slotted across "glory holes" in southeast corner of park to maximize pond capacity before allowing excess water to flow into side channels...
Wooden boards are slotted across "glory holes" in southeast corner of park to maximize pond capacity before allowing excess water to flow into side channels...
NOVEMBER 14, 2002
The dredging water enters Shollenberger Park...
The dredging water enters Shollenberger Park...
NOVEMBER 11th, 2002
Pipe from the the Dredge Barges to Shollenberger park is being laid...
Pipe from the the Dredge Barges to Shollenberger park is being laid...
Cutterblade
NOVEMBER 10, 2002
I was fortunate today to meet the project director for the dredging Dan Fox, of Nova, the company that has the contract with the Corps of Engineers. The dredging is supposed to start tomorrow, near the mouth of Adobe Creek. Nova has a 60-day contract but hopes to complete the job before the year ends.
The area dredged will be from Shollenberger north to the Turning Basin, and 11,000 feet south of the park (approximately two miles). A large Cutter Head (see photos below) will churn up the bottom and a pipe directly behind will be used to suck up the spoils . The mouth of the pipe is curved and called a Clowns Mouth This is not visible in the photo. The spoils will be pumped through 20 inch flexible pipes that come in sections as long as 1500 feet. The pipe will be buried under the hiking trail that parallels the river about 250 feet south of where the paved trail ends. It has already been laid on the other side of the path (see photos below), crossing the field and topping the dirt berm where the middle Borrow Area shows on the map.
I was fortunate today to meet the project director for the dredging Dan Fox, of Nova, the company that has the contract with the Corps of Engineers. The dredging is supposed to start tomorrow, near the mouth of Adobe Creek. Nova has a 60-day contract but hopes to complete the job before the year ends.
The area dredged will be from Shollenberger north to the Turning Basin, and 11,000 feet south of the park (approximately two miles). A large Cutter Head (see photos below) will churn up the bottom and a pipe directly behind will be used to suck up the spoils . The mouth of the pipe is curved and called a Clowns Mouth This is not visible in the photo. The spoils will be pumped through 20 inch flexible pipes that come in sections as long as 1500 feet. The pipe will be buried under the hiking trail that parallels the river about 250 feet south of where the paved trail ends. It has already been laid on the other side of the path (see photos below), crossing the field and topping the dirt berm where the middle Borrow Area shows on the map.
Dredge Pipe being laid in Shollenberger Park
NOVEMBER 5, 2002
The dredging barge and equipment are now sitting on the Petaluma River adjacent to Shollenberger Park
The dredging barge and equipment are now sitting on the Petaluma River adjacent to Shollenberger Park
OCTOBER 16, 2002
Building of the dike to isolate the Pickleweed from the dredging has begun
Building of the dike to isolate the Pickleweed from the dredging has begun