I wanted to apologize for the scarcity of posts lately. We have been busy with other photography commissions. However we are working on our letter to MEPA and the DEP concerning the appeal of the ConCom decision and we will soon be collaborating with the Nantucket Land Council on projects involving hard armoring on the island including the geotube installation.
We will have bluff updates as soon as possible and are also working on several art projects that we are completing.
I will always remember the first time I saw Orange Street. I loved the curve of the street from the hill with the rows of houses stair-stepping down. I was enchanted by the captain’s houses, built close together and close to the street. It was all new to me coming from Texas with its sprawling subdivisions. I recently spent some time exploring Orange, Fair and Pine streets and photographing the architecture of neighborhoods with houses over 200 years old. The modern world intrudes with cars and telephone poles lining the streets. I found a Smart Car parked by iron hitching posts. The architecture goes from fancy to funky the further from town you get. I watched people working on houses, working in houses and working on their vacations. I found many friendly people who were willing to stop and chat and a number of them graciously allowed me to take their photo. You can view the slideshow by clicking on the link below. ~ Sharon
The Massachusetts DEP and EPA held a joint site visit and public hearing today on a vacant lot that was once the location of a Baxter Road house. The occasion was part of a Notice of Environmental Review for the SBPF’s “Baxter Road and Sconset Bluff Stabilization Project”. Accepting public comment for the DEP was Jim Mahala, and for MEPA, Enviromental Analyst Purvi Patel. The hearing was largely an opportunity for proponents and opponents to preach to their respective choirs, swaying no one. As one official put it, “This is the first ‘onsite’ I’ve been to that wasn’t actually on site!” Few of the attendees took the time to peer over the edge of the bluff, let alone venture to the beach itself to see the geotube installation that is the subject of this environmental review. After the public input, DEP’s Jim Mahala, ConCom’s Jeff Carlson and Town Counsel George Pucci went down to the the installation to see the conditions first-hand.
Although the event was taped for the public record, the best opportunity for input is by emailing Mr. Mahala at DEP and Ms. Patel at MEPA. They may be reached at these respective addresses:
DEP representative Jim Mahala (center) speaks with members of the Nantucket Conservation Commission prior to the hearing.
An estimated 100 people attended the hearing at 97 Baxter Road.
Mr. Mahala addresses the attendees.
DEP’s Jim Mahala on the geotube installation with ConCom Administrator Jeff Carlson. (photograph by Dirck Van Lieu)
While this weekend’s work on the Sankaty geotubes may appear to be an attempt to make the installation look good in advance of Wednesday’s visit from the Massachusetts DEP, it looks more like the destruction of evidence, evidence that the tubes have not been challenged by the ocean, have had no effect on the highly active run-off from above and done absolutely nothing to protect the bluff from erosion. A new feature of this dressing-up is the many machine trips along the top of the installation, around the south end and across the front on the beach. Prior to this exercise, there were huge mounds of sediment on top the tubes, deep cuts through them, and additional fields of sediment arrayed along the ocean side. Now the mounds are gone and the beach has been sanitized by careful grading along an approximately 20′ wide swath between tubes and water. The work was apparently about more than just filling the fissures in the sand envelope. Much of the evidence of the impact of the run-off erosion has been minimized or eliminated altogether.
It’s ironic that the builders got the material for this maintenance courtesy of the bluff itself. Virtually all of the sand and sediment used to fill the fissures in the envelope was from what washed down to the top of the tubes. The sand plumes conveyed to the site for that purpose remain untouched, as shown in the photos below.
More and larger photos are on Nantucket Erosion.
A well-traveled path. Many machine trips were made between the top of the geotubes and the face of the envelope.
More than just a route, the beach was the site of a fair amount of grading work not necessary for the re-covering of the tubes.
Photo taken on August 3rd shows one of several deep, wide deposits of sediment from the bluff in front of the tubes.
August 17th: The beach has been extensively graded along half of its length, eliminating much of the evidence of top-down erosion.
Is the beach contributing to the installation instead of the installation contributing to the beach?
A prodigious amount of “former bluff” collected on the top of the tubes, photo taken August 3, 2014
Another large volume of mostly native material (not pit sand) dropped to the tubes. This was redistributed by machine 2 weeks later, leaving the delivered sand untouched.
The re-dressed top of the geotube installation. As shown by the undisturbed front edge of the sand envelope, the elevation was not lowered by scraping material off to fill fissures and otherwise maintain the envelope. All the fill for that purpose came from the eroded bank itself.
The eroded parts of the bank show vertical faces where the machine scraped away material. The plumes of delivered sand still slope directly to the surface of the envelope.
In spite of a professed interest in preserving the bluff, homeowners’ contractors are again digging into its face for fill.
Last night a brief summer storm passed over Nantucket, lighting the skies with bolts of lightning. We hurried to Tom Nevers and stood on the site of the old Navy base at the point where the road drops abruptly to the beach below. The sun had set but the sky to the west still held some light and color. We joined another local couple who informed us that we may have missed the best of the display, but there was still more to see. As the sky darkened and lightning danced across the ocean, we were joined by a man and his son who had left the golf course to see the show. Moments like these we enjoy the most, times when a group of us stand and admire the beautiful world we share.
A weekend of substantial rain washed more of Sankaty Bluff onto the beach, carving deeper into the face along Baxter Road and spreading sediment over, around and through the geotubes installed last winter. The recent weather has once again underlined two facts: the the bluff’s greatest current threat is run-off erosion from the top, and there has been no notable toe erosion (the geotubes’ raison d’être) in the area for a long time.
The sediment from the bluff, so unlike the fill from the mid-island pits, is finer and darker than the sand, giving the beach the look of a vast marble cake. As the rills cut ever closer to the road, huge volumes make their way to the ocean. The different colored materials that remain intact in front of the tubes show that the waves still come nowhere near washing up against the armoring.
More and larger photos are on Nantucket Erosion.
The bank, from the the former site of Bluff House to Swept Away, is only partially fronted by geotubes, but the erosion from the top is the same whether “protected” or not.
The ends of the installation are sloped, ostensibly to provide pedestrian access to the top of the tubes.
The north and south ends of Swept Away are major collection points for run-off, and as a result, are major areas of erosion.
The volume of sand and sediment at the bottom of this cut is far more than would fit back in it, so it must be coming from other places.
The path to the sea.
The north side of Swept Away. As the bank is eroded back on both sides, the house will find itself on a peninsula of sorts. It is evident that this much material is coming not only from the bluff face.
The stream from the north side of Swept Away has cut more than 5′ through the sand envelope.
The folding rule rests against an exposed geotube near one of the seams that run along its length.
We have spent several seasons photographing the carnival that comes to Nantucket in the summer. The small and shabby midway appeared this year after the film, comedy, and wine fests and before the music and dance fests. There is no way to make this event fit the Chamber of Commerce image of Nantucket – you can’t slap a whale tail on it, you can’t make it precious or preppy. It is a carnival after all, with carnies and bad food and tired rides. It’s dead until the people get there and it takes lots of them to bring it to life. The small crowds are made up of locals, seasonal workers and a few vacationers, less lily white than the Lilly Pulitzer crowds elsewhere on Nantucket. The most remarkable thing about it is how like every other carnival it is.
When we went back this year to photograph this event, we were struck by how little effort was put into maintaining the happy illusion. It felt like everyone was too tired to try. The Ferris Wheel was mostly unlit and every ride seemed to be missing lights. Some rides had been downgraded from cars that were colorfully painted to plain white, unlit cars. Light bulbs were out everywhere. A few workers were friendly, others seemed depressed and still others were downright hostile. The poor lighting meant that the shadowy places were more obvious, the darkness was easier to see. Our photos show noticeably less joy on the faces at the current carnival, and little of the enthusiasm of the attendees two years ago. A few even show the menace we felt from some of the staff.
We began this series to show the small patch of magic where, once a year, we agree that an inflatable shark is worth the $10 or $15 to win it, and that fried dough is a treat even if we will never think of it again until next July. This year though, we were confronted by more shadows and less magic, represented by the missing lights and the dark silhouettes. We looked at our pictures at night after reading news stories of children blown apart, raped, hanged and shot from the sky. Children on the world’s midway at night – the darkness hidden in the shadow of the lights. If we have ever loved one child, we have loved them all and wish we had held them closer and hope that we have never added to the darkness. We wish the world was better. We know the darkness is there, yet we do too little. We avert our eyes from the carnies, agreeing to the bargain. It’s just a carnival.
“…and the shining is as thick darkness.” Job 10:22
We drove past the Carnival at the fairgrounds to a favorite stretch of beach last night. Dirck had only taken the time after dinner to pull off his boots and grab his fishing rod. It’s always a pleasure in the summer to find a quiet beach to enjoy after navigating traffic and crowds all day. Last night, a friend was there with his dogs. He and Dirck visited and cast a few times while I wandered around photographing. We all took time to enjoy the glorious sunset.
This morning we received an email from the Sconset Beach Preservation Fund ostensibly updating the “performance” of what they termed the ‘Sconset erosion project. It claimed that “the system worked well… ” during the recent storm, “…preventing any undermining of the toe of the bluff.” It went on to assert that “the challenging problem of erosion from ocean waves has been controlled once again”. These are total fabrications, and poor, careless ones at that, given that the email included an attached photo proving beyond any doubt that the waves never came near enough to even wash away the eroded sediment extending perhaps 10′ in front of the geotube structure. Not only did the waves never threaten the toe of the bluff, they never even came close to the sand envelope covering (for the most part) the tubes.
The eroded sediment that flowed through the geotube structure fans out onto the beach, untouched by the tides that never came close to the armoring.
Some six months after the incomplete installation of the geotubes, the SBPF is finally acknowledging the impact of rain run-off. This “Day Late-Dollar Short” recognition of the significance of the top-down erosion is indicated in the email by a reference to “unnecessary garden variety erosion from storm water”. Such erosion has been an issue on Baxter Road for years, and is not now, nor will ever will be addressed by engineered structures on the beach, be they jute bags, geotubes or rock revetments.
In closing, the SBPF’s email invites the public to their new viewing area to see “how the erosion project is functioning.” They have picked an ideal spot, given that the area is immediately adjacent to a notably active, dramatic erosion location. If they decide to provide an equally accessible view to see how their anti-erosion project is working, they will have a tougher choice.
To see photos showing the run-off erosion from Hurricane Arthur, and the untouched geotubes, please visit Nantucket Erosion.
The 4th of July brings with it the certainty that winter and its battering storms are past, and another summer of promise is here. This year it also brought a hurricane, reminding us that winter storms are often followed by a season of tropical storms, some of which make it this far north. Hurricane Arthur dropped a huge amount of rain and not a few tree limbs on Nantucket, and further eroded the Sankaty Bluff in the same manner as other rains since the installation of the SBPF’s geotubes; it washed a great deal of bank away from the top and down the face, spreading sediment on top of the geotube structure in some cases and carving deeply through it in others. In spite of this heavy weather, there was still none of the toe erosion that has captured the focus of the engineering below.
It is interesting to contrast the efforts to combat erosion at the bottom of the bluff to those at the top. Millions of dollars and a small mechanized army were brought to bear against the waves of Sankaty Beach, but the run-off at the top, an issue of great significance, was only considered as an afterthought and addressed by the installation of a few pieces of unpermitted PVC pipe, several boards and a few stakes driven into the ground. Just two weeks ago we predicted in a previous post that those measures would simply move the problem to one side or the other because the collected rain would simply run around obstacles placed in its path. That’s exactly what happened.
More photos are on Nantucket Erosion.
Continuing degradation at the former site of “Bluff House”, where the rainwater-driven erosion is working its way back through the fill used to cover the old foundation excavation. The SBPF has installed a new viewing pen adjacent to the cut.
Sediment from the bank spread over the top of the geotubes and the beach, undisturbed by the ocean.
An obstruction placed in the path of heavy run-off expanded the deep erosion to the neighboring lot.
A deep, wide cut into the sand envelope covering the geotubes.
The dramatic loss of material is entirely attributable to rain run-off from above. This area is untouched by the waves.
The 4″ PVC pipe that was meant to stop the erosion from the top has been exposed by the torrents of rainwater.
Although the unpermitted pipe was never connected, it would clearly have been overmatched and ineffective given the sheer volume of rain running over the edge.
The lot of “Swept Away” is bracketed by deep cuts from top-down erosion. The two sides differ in that one is carved by rainwater from the surface while the other (above) is also cut away by water exiting the bluff face perhaps 6′ to 8′ below the surface.
The photograph above shows the level at which the run-off, presumably from the wetland across Baxter Road, comes out. The line of gray sediment running down the face gathers into a stream and makes its way to the top of the tubes below. It’s notable that the bank above this level is relatively dry. We could see chunks of earth falling as we shot this area.
A closeup of the gray sediment running out of the face of the bluff, far below the surface. It illustrates the complexity of the erosion and why a “one-size-fits-all” attempt at countering it is so likely to fail.
The SBPF has filed an appeal of the recent ConCom decision denying their Sankaty Bluff geotube project. We ask the Judge to do the right thing and uphold our commission’s decision. Whatever the outcome, an environmental legacy is at stake and the members of the Conservation Commission will be seen as having worked to protect Nantucket’s fragile environment and beaches. We hope that the few who, in their self-interest want to build sea walls that will destroy Sconset Beach will not prevail .
“I think having land and not ruining it is the most beautiful art that anybody could ever want to own.” – Andy Warhol
We hope the judge protects the town’s beach and doesn’t allow it to be ruined further.
The advice given to those afraid of heights is “Don’t look down.” The same advice could apply to those who wish to understand the current dynamics of the erosion of Sankaty Bluff. We are past the winter storm season and the sand envelope covering the geotubes remains essentially untouched from the ocean side. It is, however, deeply carved by rainwater run-off from the top of the bluff. Looking down from the edge will show the effect of the run-off on the engineered structure, but one has to keep eyes on the top to see the sources and the reasons for the substantial changes.
There has been no obvious effort made to handle the rain that falls on Baxter Road and its surroundings. There are no storm drains nor culverts nor even ditches to accommodate the considerable accumulation. The rain and excess irrigation are left to follow whatever paths gravity dictates, and for much of it, those paths lead over the bluff and onto the beach. Once over the edge, the water carries sand and rock down the face to the bottom, gathering more materials along the way. Some small efforts have been made to stop the erosion of the bluff top by damming its edge in places, but, incomprehensibly, these efforts ignore the the volume of water that will continue to run across the pavement and empty lots to find its way over the side. At best, the damming will divert the run-off slightly to one side or another until a new channel is carved into the bank and new losses are sustained mere feet away from the existing.
There are several reasons why the erosion of the bluff top has accelerated. We suggest that the removal of houses has left the bank in a weakened state. In several places where there were once deep foundations and footings or full basements, there are now cavities filled with uncompacted fill that is particularly susceptible to erosion. It seems logical that the more digging, filling and operating of heavy machinery one does in this vulnerable place, the more damage one will do. For this reason we find it counter-intuitive that people moving houses would again dig full basements so close to the edge, or in some cases dig them where there were none before. We wonder about the stability of the bank where old foundation holes were filled with pit sand. It’s easily imagined that once the erosion reaches these soft spots, the rate of loss will increase as it has at the former “Bluff House” site.
More photos are on Nantucket Erosion.
The former site of “Bluff House”, where the erosion has intruded into the fill, reaching a point just 55′ from the edge of Baxter Road.
The erosion is deeper than is first evident. The surface is undercut by 18″ from the edge of the grass.
Some houses now have full basements although they did not prior to moving.
“Slip Slidin’ Away” has always had a full basement, now the old one must be filled. As evident in the photo below, the new siting has gained very little room on the water side.
This was the site of three major erosion cuts made by run-off from the road and adjacent vacant lot. The grade has been raised to turn the water aside. Given that the water will still come, it’s reasonable to predict that it will cut new fissures to the left and right of this elevated section. This can be considered representative of erosion control efforts in general; they make the problem “someone else’s problem”.
In a recent email, the Sconset Beach Preservation Fund expressed the contempt with which they hold our Conservation Commission and the people of Nantucket. They called the ConCom decision “flawed ideological thinking”and said that the commission had ignored the science, the facts and the law. We believe the Conservation Commission made the right decision, protecting not only the beach and bluff in Sconset but also the island itself. We feel the SBPF’s determination to consume Nantucket’s beaches and natural resources while contributing to the erosion from the top of the bluff is a grave threat to Nantucket’s future. Our beaches are a vital part of Nantucket’s great appeal and a cornerstone of our island’s economy. We doubt that travel magazines will recommend Nantucket to their readers as a place with one of the “10 Best Geotubes”.
The ConCom and those who support them in this decision are not the reasons the bluff is still eroding and they will not be the reasons that houses and roads will have to be moved. Those things will happen because the houses are built on a sandy bluff facing the Atlantic Ocean. One may keep a house with its current siting a year or two longer, but it is not worth the destruction of public beaches to do so.
We would like to address the SBPF’s flawed thinking and state why we have every confidence that the ConCom made the correct decision.
Reason Number 1 - THE GEOTUBES AREN’T STOPPING THE EROSION.
The bluff has continued to erode in dramatic fashion after the geotubes were installed. One might think that the discussion of the tube’s appropriateness could end right there. Instead, we have heard the SBPF declare the tubes a success, although we have never heard them explain how they measure that success. There is very much less bluff than there was before this installation. The only verifiable success is that the tubes are still intact. As we have said time and time again, the tubes’ own survival is not their purpose nor is it any indication that they are succeeding.
Although these photographs of the bluff over the tubes and were taken 5 days apart, the difference came in one day. The photograph above was taken on June 1, 2014, the one below on June 5, 2014. This is after a night of rain, not a 3-day nor’easter or blizzard.
Photograph above taken in February 2014 after the geotubes were installed. Dirck is standing on top of the tubes behind the large boulders that fell from the bluff face.
The photographs above and below were taken two months apart after the geotubes were installed.
Reason Number 2 – SBPF’S ENGINEERED EFFORTS TO STOP EROSION IGNORE THE FACTS, THE SCIENCE AND THE LAW
After what appeared to be a reluctant acknowledgement of the effects of run-off from the top, the SBPF installed an unpermitted length of 4″ PVC pipe to transport rainwater to a drywell dug into the top of the installation. The pipe is too deep to address the surface run-off and too shallow to collect any of the water migrating from the adjacent wetland to the bluff face. It is also woefully inadequate to handle the volume of an ordinary rain. Given that we were told that its purpose was to handle road run-off, we are left to wonder if the SBPF’s engineers consulted with the project’s co-applicants, the Town of Nantucket and our DPW.
After the PVC pipe was left capped and off-line, some boards were staked into the rainwater breakouts, one notably being where the pipe is buried. A minimum of applied science, engineering or even common sense should tell one that rainwater would either stop at those dams, creating Baxter Lake, or would simply go around them, eroding their supports, widening the breakouts and continuing to do the same sort of damage as before.
The SBPF engineer’s solution to road runoff involved throwing some 4″ pvc pipe over the side, ignoring the facts, the science and the law.
The engineers used more advanced scientific methods the second time around – boards and straw. Photo above taken on June 1, 2014. The one below taken on June 6, 2014.
Reason Number 3 – WE BELIEVE THE SBPF HAS GIVEN MISLEADING AND INCORRECT INFORMATION TO THE CONCOM, THE MASS DEP, AND THE PUBLIC.
The SBPF has made claims of 40′ losses of the bank in the “previous year” at the site of “Bluff House” to the MASS DEP in their application for an emergency certification allowing the geotube installation. This claim was cited in the DEP’s issuance of that certificate. The photo maps they used to substantiate this claim are duplicates, identical save for lines drawn on one to represent the edge during the previous year. Our photos show beyond dispute that the loss is nowhere near that amount over a period of 16 months.
The photographs above and below were taken 16 months apart – nowhere near a 40 foot loss.
SBPF representatives told ConCom that unapproved plastic sheeting exposed after a storm was only used in a small section of the installation and was removed by the managing company. We have photographs of this sheeting used in a number of places throughout the installation. This environmentally harmful material is still in the geotube structure, with the potential to be released during future storms.
The material in between the two geotubes in the lower left of this photograph is plastic sheeting.
An SBPF representative stated in a recent interview on Geno TV that a house that was moved from the bluff to Monomoy was no longer generating tax income for the town. We think it is more than likely that the owners still pay taxes on their Monomoy home. That representative also said in the same interview that the sand coming from the middle of the island and being poured over the edge and, in effect, into the ocean is the same as Sconset beach sand. Anyone can look over the side of the bluff now and see that the sand is different. The sand coming from the middle of the island is not the same as the sediment (silt, clay, sand and soil) that the bluff contributes to this and other beaches..
The above photograph of Dirck and meteorologist Tim Kelley of NECN on top of the geotubes was taken in May 2014. The difference in the sand from mid-island and the beach sand is obvious.
Pit sand on the left side of the photograph above and natural bluff material on the right. Obviously different material.
Reason Number 4 – THE GEOTUBE PROJECT, ESPECIALLY IN IT’S PROPOSED 4100′ LENGTH, WILL EMPTY THE ISLAND OF AVAILABLE SAND
The geotube installation will do what this type of project does nearly everywhere – it will deplete local sand sources. Builders, landscapers and DPW road crews will have to pay more to have sand barged in. This sand taken from the middle of Nantucket and poured into the ocean will never be replaced. Once gone, it is gone forever and future generations will bear the consequences of the SBPF’s proposed depletion of our natural resources.
Reason Number 5- THE GEOTUBES HAVE DESTROYED THE WETLAND SCENIC VIEW.
Is this anyone’s idea of a beach?
An SBPF spokesman said that the geotubes would be recovered only in November and April, meaning that this could be our scenic view for much of the year.
We passed a car in Sconset today that wore an SBPF bumper sticker . The sticker read “Retreat Will Not Save ‘Sconset”, implying that the entire village of Sconset is under threat from the erosion of Sankaty Bluff. Of course it’s only a section of Baxter Road that is under threat, the dead-end to the North. While this neighborhood is a valued part of the island’s past and present, it is only a small part of the village. The reference to retreat is nearly an accusation of a lack of warlike resolve, even cowardice. It’s a call to arms that declares that it’s time for steely-eyed men to stand up to mother nature and “close the wall up” as Shakespeare’s King Henry V urged.
“…lend the eye a terrible aspect;
Let pry through the portage of the head
Like the brass cannon; let the brow o’erwhelm it
As fearfully as doth a galled rock
O’erhang and jutty his confounded base,
Swill’d with the wild and wasteful ocean.”
What we saw done to try to stop the “wild and wasteful ocean” seemed more of a threat to the bluff than any natural event.
More photos are on Nantucket Erosion.
The stairs that provide public access to the beach below the Sankaty Bluff are bracketed by new attempts to armor the bottom. Sand has been dropped by chute (above) to be used as fill for jute tubes that have been added over the existing tiers.
Ironically, vegetation was removed from the vulnerable top edge of the bank to facilitate dumping sand to a point where there has been no toe erosion in recent memory.
Not much concern for free access here. It appears that the bank was cut into on both sides of the stairs to place the top tubes. The sand on the steps is fill already released from the jute mere days after its installation. A soft swipe of the sand shows new fill pouring out to replace what was scraped away.
The chute, new jute tubes and plumes of sand dumped over the edge of the bluff.
New tubes that appear to have been cut into the toe of the bluff.
At the geotube site, a graphic representation of the mismatch of pit sand to natural bluff material. To the left is the pit sand, to the right, the sand, soil, clay and sediment given up by the bluff under natural conditions. State and local wetlands bylaws require the new material to be compatible with that on site.
When the geotubes were covered after initial erosion losses, a dam was created at the juncture of structure and bank, preventing the natural sediment from reaching the beach. Note that the angle of repose of the sediment is much flatter than the adjacent bank, showing the ease with which it would ordinarily continue on.
Dumbfounded: The Sequel.
When we first saw this zig-zag path cut down the face of the bluff in an area close to the road-closing trigger point, we thought it was vandalism. It seemed impossible for anyone concerned with the bluff erosion to cut deeply into the bank back and forth across such a wide swath, weakening the already vulnerable face. Then we saw the line of beach grass marching to the bottom! Was this to lend some air of legitimacy to the cuts or is the grass supposed to stabilize the path itself?
One thing is for certain; these thin lines of grass will have no effect on the erosion of Sankaty Bluff.
We are reorganizing our site – Nantucket Erosion – to get ready for the next phase of our work. We will let you know when the new site is ready. In the meantime, if you have any questions, please email us.
The Conservation Commission held a special session tonight devoted to making official the findings for the drafting of the final denial order of conditions for the geotube installation below Sconset Bluff. We have been impressed with the thoroughness of the commission during the many months of hearings for this project. They have listened to hours of testimony and pored over many pages of written submissions, charts and graphs. Nantucket is fortunate to have such a high level of expertise in this vitally important body.
In a 4-2 vote this afternoon, the Conservation Commission began the process of denying the Notice of Intent of the SBPF/Town geotube project on Sankaty Bluff. The meeting will continue next week and the formal denial will then be prepared. The meeting was filmed and will be available to watch on the town website.
Here is the NECN report on the geotubes. It was interesting to watch their total coverage this morning which has lasted several hours. They didn’t have any coverage of successful geotubes.
They used quite a few of our photos and videos.
Click on the photo to see the video –
If you are interested in coastal management and rising sea levels, you will want to be here today. Thanks to Nantucket Coastal Conservancy, the Nantucket Civic League and the UMASS Boston School for the Environment for bringing Cornelia Dean and Dr. Robert Young to Nantucket.
The bluff at Sankaty has been subject to toe erosion throughout its history, but now significant portions of it are covered by jute tubes, and more recently, geotextile tubes. It’s interesting to see that, of late, there is little discernible difference in the impact of the ocean on the covered and uncovered areas. This is not to suggest that the bluff will never again be washed by the waves, only that it continues to erode at a rapid rate in spite of the engineering of beach and bank. The only active erosion currently is from the top of the bluff and its face. While attempts have been made to attribute this erosion to a rise in the sea level, no one could sensibly claim that it is responsible for the decay of the upper edges of the bluff as sand, soil and sediment wash down to be deposited at the toe.
The rainwater that pours over the edge is not a product of rising sea levels. The water and sediment from the wetlands across Baxter Road coming out of the face of the bluff are not the products of rising sea levels. They will not be stopped by engineered structures on the beach and they will not be stopped by nets and “hair plugs” if such volumes continue to flow under the added layers.
More photos are on Nantucket Erosion.
New jute tubes have been added near the public access to the beach. Waves have not touched this area of the bluff for a long time.
In spite of the absence of toe erosion here, the bank has eroded dramatically since the rebuilding of the stairs one year ago. Now the stairs themselves are under threat.
The only toe erosion of note has been caused by machines, here and at the stairs where the lower edge appears to have been dug out to fit the tubes tightly to the bank.
A machine has dug past the supply of sand dumped from the top and has cut into the bank itself.
Stark evidence that not all the run-off is from the surface. The long, horizontal cavity that appears approximately 10′ below the edge is the level at which water and sediment exit the bluff face from the wetlands across the road. There is no similar erosion above this cavity.
One of the large cavities forming below the edge.
A detail of the level where the blue/gray sediment is flowing out of the bluff face far below the edge, showing the cavitation.
There has long been a ladder to nowhere at this point over the geotubes, but now someone has cut a zig-zag path down to the installation.
It took a lot of shovel work to cut this into the bluff.