After another night of rain and wind, we made a trip to the bluff. It was interesting to see areas over the sand plumes where the water can be seen disappearing into the sand, apparently continuing out of sight, to the inside of the geotube structure.

The lot where Bluff House stood and the lot next to Bluff Edge – both areas where the conveyor belts delivered sand – are major channels of runoff as the lots are bare of vegetation for the most part.

Slip Slidin’ Away seems to be getting very close to being difficult to move.

More photos are on Nantucket Erosion.

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When the Nantucket Board of Selectmen approved a public/private partnership for the installation of geotubes on a town-owned beach, they set a precedent for how the town deals with erosion. Even though the people of Nantucket repeatedly rejected questionable proposals to address the erosion of Sankaty Bluff, a simple majority of selectmen voted to allow hard armoring, a method prohibited in all but special circumstances. With this project came intense public scrutiny, but the town did nothing to provide the appropriate monitoring that a project of this scope would require. As a result, some conditions of the emergency certification were not met and some violations ensued.

In evidence submitted to the Massachusetts Department of Environmental Protection, the SBPF claimed that Bluff House lost 40 feet in one year, a “fact” cited in the DEP’s Regional Director Philip Weinberg’s letter informing the SBPF’s attorney David S Weiss of the issuance of the emergency certificate. This claim has to be seen as impetus for the support from the Board of Selectman and the Nantucket Conservation Commission, and for the approval by Director Weinberg, and yet it is clearly false. Was everything that the SBPF claimed simply taken at face value? Our photographs do not support that claim. Did the Board of Selectmen do anything to investigate whether such claims were true?

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The photograph above was taken on November 23, 2011, the one below was taken on March 8, 2013, 16 months later. There was not a 40 foot loss in one year as stated in the DEP filing.

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As we have observed the bluff for the past 5 years, we have watched large streams of sediment running down the face of the bluff from the wetlands across Baxter Road and we have seen the effect of water pouring over the edge. Yet runoff was not adequately addressed in this installation. The geotubes may well protect the toe of the bluff from wave action but they do nothing to address runoff. We have seen the bluff continue to erode onto the geotubes with unimpeded rivers of sediment, gravel, rocks, and boulders. We are now watching an area of sinking sand caused by apparent erosion within the structure. The Board of Selectmen were bombarded with paperwork from the SBPF ostensibly explaining why the geotubes were essential to save Baxter Road, but did the three members who voted for the tubes actually go to observe the bluff for themselves? Anyone could see what is happening now and what has been happening for years just by standing on the beach below.

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The above photo of the runoff and erosion below Swept Away was taken on December 15, 2013, the one below was taken on March 8, 2014.

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We have attended ConCom meetings and heard misinformation given by representatives of the town. At times, “misinformation” seems like an overly generous term. In a recent meeting when questioned about unapproved plastic sheeting that was left in the installation, (where it is now being exposed and is losing pieces to the ocean) town staff stated that the plastic was used to keep water off the geotubes. Truly an alarming statement if the town is using materials on the beach that can’t get wet. The project manager, in a correction, said that the sheeting was used under the pump and hopper. However he then said that he had removed the exposed plastic sheeting, implying the problem was solved. Our photos show that there are at least two large sections of the plastic left in the installation, which eventually could end up in the ocean. It’s hard to accept assertions that town employees were on site nearly every day during the installation given that the four enforcement orders from the ConCom addressed violations that were brought to light by private parties. We can only conclude that there was insufficient town presence or that those monitoring did not understand what they were looking at.

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One of at least two pieces of polyethylene sheeting left on site.

We have been told by the owner of FishTec, the company that installed the geotubes and by the project manager that we know more about the geotubes than anyone else on island and we are very appreciative of their willingness to allow us to document the installation and answer our questions. They were always free with information and gave us access limited only by safe practices. As a result, we have terrabytes of photographs and a fairly comprehensive knowledge of how the geotubes were installed. But we think it’s unfortunate that there wasn’t adequate town oversight in place to report to the Board of Selectmen and the ConCom. The Board of Selectmen should have insured that thorough, ongoing documentation was provided directly for them. A justifiably self-interested group such as the SBPF should not be left to decide what is done when that interest does not necessarily coincide with the will of many of the people of Nantucket, not even all of Baxter Road or Sconset.

One of our selectmen told us that it was ConCom’s job to oversee this project. To ask the ConCom to oversee something of this size and scope and importance without adequate resources is to allow inaccurate assumptions to go unchallenged and work outside of the permissible to go unnoticed. While we understand the nature of the work (and burdens) of volunteer boards, we call for the necessary staffing and support to protect the island’s interests now and in the future.

When history writes of this episode in years to come, we think the folly of this venture will be exposed and those who allowed it to happen and those who implemented and funded it will be known as the people who destroyed what cannot be replaced to try to save what cannot be saved.

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The very phrase “100 Year Storm” conjures images of a dramatic weather event with widespread destruction from an angry sea, but no one will shudder at the thought of a garden-variety rainy night. The effect of one night of rain on the Sankaty Bluff is impressive in its own right when one considers the changes brought to the edge and face of the bank and the geotube installation below. The greatest change seems to be at “Swept Away” and the former site of “Bluff House”. Rainwater over the top has carried down large amounts of new sand and old sediment, washing the fine material over the tubes and into the tide.

One of the deepest rills appears very near where the PVC pipe was buried in the sand plume next to “Swept Away”. Ironically, the source of run-off that dug this trench is not from the area where the perforated drain pipe was installed, but from far across the “Bluff House” lot. Evidence of a considerable stream traveling 100′ to the edge is easily seen in the dirt. Another very deep rill is fed from a long swale on the same lot.

It would seem that run-off is doing more than simply running down the face of the bluff and into the ocean. We have been keeping an eye on a 60′ stretch on the top of the sand envelope that is definitely sinking. This area, below “Swept Away”, is 9′ wide in places, is bordered by fissures in the sand and is 6 to 8″ lower than adjacent elevations. (See 3rd photo below) There are other areas where the run-off percolates down into the installation as well, as shown in the 4th photo. While looking for a possible explanation, we went back over photos taken during the installation of the second tier and found that the overlaps of both the first and second tiers were placed very close together instead of being separated as much as possible, as a mason or a shingler might do. This creates two voids, back to front, in close proximity, that could allow for erosion within the structure. What is incontrovertible, however, is that that the surface is dropping above those laps and the underlying material is going somewhere.

Early in the project, we asked the owner of the installing company how run-off behind the tubes would affect the structure. His answer was simple. “I don’t know.” He allowed that, although he had installed miles of geotube, he had never done a project up against a bank. We’ll be watching this area and other percolating spots to see how they fare.

More photos are on Nantucket Erosion.

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The top down erosion continues at the edge of Sankaty Bluff. The profile has changed considerably since our last visit, and parts of the fence at the last house have given way. A depression at the top noticed a couple of weeks ago is much deeper, and some of the cracks have widened to the point where the grasses have let go.

More photos are on Nantucket Erosion.

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I was told, after a recent Conservation Commission Meeting, that my love for the eroding bluff was like that of someone who liked dilapidated buildings. I was surprised at this as it’s hard for me to contemplate that some people don’t see Sankaty’s natural beauty. I realize that we will not agree and I accept that. We are told that we will be able to walk the tubes as we now walk the beach, yet walking on the elevated structure will not be like walking on a beach. There will be no waves lapping at your feet, no seaweed and horseshoe crab shells, no skate egg sacks and no driftwood. It will be more like walking on a dirt road than on the beach it was.

This post is for those who live here or come in the summer because of their love of this wild island with its craggy banks and its wind-bent trees, who like to stand in the teeth of a storm to hear the ocean roar, who recognize that the incredible privilege of living on this island means living with change. I hope that when our generation is gone, it leaves the island as it is meant to be, not with barricaded beaches vainly attempting to control the ocean’s course.

Sharon

Please visit This Unworthy Beach  for an accompanying collection of larger photographs.

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The March blizzard is five days gone, and while erosion of the Sankaty geotube installation continues, it’s the bluff itself that attracts our attention.  One might think that the sand poured on its face has slowed its decay, as the visible areas of run-off are at the edges of the plumes and the impressive erosion appears to be on the bare sections, but the volumes of water from the top have to be going somewhere. It’s obvious that they are not pooling on the road or the top of the bluff, and they show no signs of running down the face of the sand plumes, encouraging speculation that the water continues to run down under the sand, and under the geotube installation. This speculation is supported by the apparent sinking of the surface of the envelope below “Swept Away”. That area, approximately 50′ long, continues to drop, and the fissures along its edge, to deepen. A new crack has appeared, indicating that a larger sink hole is imminent.

To the north, still within the area ostensibly protected by the geotubes, a large, dome-shaped section below the ladder (see first photo below) has dropped some and appears ready to let go entirely. This is the kind of loss associated not with wind, rain or run-off, but with the erosion of the toe of the bank. This toe happens to be on top of the tubes.

EDIT: Added a photo showing the area below the ladder on the north end of the installation that is eroded. This photo was taken March 31, 2014.

More photos are on Nantucket Erosion.

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Two days after the March blizzard exposed the geotubes below Sankaty Bluff, we returned to the bottom to see the state of the installation. The natural tide cycles have redeposited a considerable amount of sand on the beach, covering all but a few small patches of the first tier of tubes. The second tier, however, is exposed much further along its length than it was the day of the storm. What’s more, a corner of the third tier is now showing on the northern end. The sand envelope mimics the bluff above it by cracking and depressing along its seaward edge before dropping to the beach. The cracks on that edge seen today suggest that quite a bit more of the third tier will see the light of day very soon, possibly during the rain and 30 mph winds predicted for the next two days.

The poly sheeting exposed over the second tier looks to have lost a couple of square yards to the elements, as there was only a small wad showing today, but a slight tug revealed a bigger section with a wind-whipped, ragged edge. Another piece was evident further up the line. The installation photo below shows the sheet spread in front of the pump and hopper. It appears to be about 20′ by 40′.

The depression at the back of the sand envelope that runs parallel to the tubes is now deeper and wider than it was six days ago. A six foot folding rule was more than enough to span the depression then but is too short to reach across now. It appears to have sunk an additional 2″ or so, and the cracks at its edge are continuous. A part of the crack that I could measure at 28″  deep last week swallowed 43″ of the rule today. The concern is that if the back of the installation is not stable, it will not be able to support the proposed netting and planting of the bluff face.

More photos are on Nantucket Erosion.

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The scene was much calmer on Sconset Beach today. I went at low tide and the beach was smooth with little wind and bright blue skies. There was plastic sheeting hanging from the tubes in several places. The bottom tube had more sand on it than it did during the storm yesterday and not as much of the anchor tube was visible.

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The late March blizzard has given the geotubes below Sankaty Bluff their first real test. While the results for Baxter Road are open to interpretation, the effect of wind and water on the beach is indisputable. The installation has lost a huge amount of sand and the tubes are exposed for a long stretch on the northern end. It is not just the first above-grade tier that’s showing, but the one installed in the trench below mean high water as well. The lines securing the scour aprons have given way, leaving the aprons in disarray, and the covers on the concrete plugs have washed off, with ropes of adhesive twisted nearby. The anchor tube in front of the first tier, meant to prevent the tide from undermining the geotube, is also exposed in two places.

On the top of the sand envelope, there are cracks in the surface between 2 and 6 feet from the edge, showing where wholesale lots of sand are about to drop into the waves. At that rate, the top tier of tubes could appear before long.

More photos are on Nantucket Erosion.

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An early trip to Sconset meant white-0ut conditions on the Milestone Road and some ripping winds on the bluff. It’s pretty woolly down on the beach, and the waves are carving away the sand not only in front of the geotubes, but along the whole shore. The wind-driven tide and stinging snow made a trip the the bottom a poor idea, so we’ll see how it looks after the tide recedes.

More photos are on Nantucket Erosion.

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This weekend afforded a good opportunity to check the state of the Sankaty Bluff and the geotube installation at its base. A climb down to the geotubes reveals a new development. There are crevasses running parallel to the top tubes, six to eight feet apart, with the surface between depressed by several inches. Yesterday, 3/22/14, I claimed that a stretch of the top is sinking, due either to the sand dropping down into old voids in the envelope or new erosion from within, but reviewing past photos, the ridge on the bank side was already showing, although the crevasses were not. While this reduces the claim to speculation, the fact remains that the crevasses run along each side of the depression. A six-foot folding rule easily dropped 24 to 36 inches into some of the cracks. Other areas of the surface are not as flat or regular as they were, but this is to be expected.

More photos are on Nantucket Erosion.

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On a trip to the Sankaty Bluff on March 16, 2014, we noticed several new cracks and areas where the ground had given way close to the edge at the narrowest part east of Baxter Road. According to the director of the town’s DPW, there was 31 feet at the narrowest section in the fall and when there is only 25 feet between the road and the bluff, they will close Baxter at that point. We measured one area where the bluff is narrowest and it will soon lose another 2-3 feet.

The first photo has a dotted line over a section that has cracked and dropped as the bluff does before it loses some of it’s edge. The second photo was taken in the area north of Bluff Edge. The third photo shows the steep incline under Swept Away, indicating the considerable amount of fill needed to reach the top edge from below, given the sand’s angle of repose.

Larger photos are on Nantucket Erosion.

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We neglected to post this set of photographs, taken on 12/27/2013, due to the rush of the holiday season. They show the installation of a return tube behind the first tier of geotubes on the north end of the project. We did not witness any other of what would be presumably at least five more returns installed. This return is no more than half the height of the tube in front of it, suggesting that it would take a stack of two to adequately protect the end of each tier from scour. We were told that no subsequent returns were installed because they weren’t part of the emergency certification and that such a change would have been too much to be made by a field decision. The emergency certification issued by Philip Weinberg, Regional Director of the Massachusetts DEP, includes this in the Special Conditions for Sconset Beach Preservation Fund Emergency Certification for 91-105 Baxter Road: “The sand-filled Geotubes shall be tapered into the beach/bank at the southern and northern ends to minimize end effects.” In the letter to the Nantucket Conservation Commission making the joint request for the emergency certification from the Town and the SBPF, attorney David S. Weiss included this in the project description: “There will be shorter return tubes on the return ends to minimize flanking.”

Now that the installation has been represented as complete, the applicants are proposing to add the missing return tubes. This will require excavating the north and south ends to the bottom of the first tier, which is entirely buried in the beach, and digging under the ends of the next two tiers to insert the stacked returns under them. The rendering of the return tube installation provided by Ocean and Coastal Consultants shows an arrangement of tubes ten high, peaking with four tubes arranged directly on top of each other with no pyramid-like base to stabilize them. This will create a vertical wall of approximately twelve feet at each end of the structure. Given that the applicants have maintained that the beach-going public will be able to walk the top of the tubes, it will take a considerable amount of sand, susceptible to end scouring, to make ramps that can be climbed to meet the new elevation created by the proposed fourth tier of geotubes. Maintaining a reasonable slope for that purpose will surely require ongoing machine work around the clay head on the north end, already identified as a geological feature not to be disturbed and one that prompted the entire installation to be moved southward.

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A visit to the Sankaty Beach geo-tubes shows little change to the beach and only moderate change to the bluff in the 10 days since maintenance was done to fill the fissures in the sand envelope and cover the exposed north end of the top tube. Moderate is a relative term with different values if you are comparing the erosion to the drama of the last two weeks or watching the edge of the bluff advance on your house.

The amount of beach in front of the tubes appears to be much as it’s been since the installation, with no evident front or end scouring. What looks like possible accretion on the south end is actually a snow drift covered by silt from higher up the bank. There remains, however, a significant amount of erosion from the top down. Sand, stones, silt and very fine sediment are working their ways down without any effect from the tides. Some of the ruins of demolished buildings are good indicators of the rate of decay. As concrete footings from a long-gone garage emerge from the bank, it’s easy to see how much more is exposed from one visit to the next.

Curiously, not all of the run-off is from the very top of the bluff. The photos show blue-gray sediment flowing from numerous places 2′ to 10′ down from the edge. It has presumably reached the light of day after flowing from the wetlands across Baxter Road on top of an impermeable layer of clay. Notable is the pool of sediment that looks much like a hide left on the sand to dry, even curling up at the edges.

In the sand envelope covering the tubes, there are voids that turn to sinkholes when walked on, and there is a narrow fissure running laterally, suggesting that sand is either dropping into a long, empty space within or is being scoured from below, although with the front intact, this seems unlikely. Time will tell.

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Slip Slidin’ Away is being prepared for its move to the lot next door. This will buy some time for it – how much is to be seen. Swept Away remains a few feet from the edge and we have seen the edge behind the Claudy house, the one closest to the lighthouse, degrade further._MG_4863

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One of the photographs from our Feet of Clay – The Revelation of Sankaty Bluff series has been used on the cover of the Nantucket Land Council‘s annual report.

Please consider helping this organization finance their important work –

The NLC is a 501 (c)(3) non-profit dedicated to protecting Nantucket’s natural world and rural character by holding and enforcing conservation restrictions, commissioning scientific research, monitoring development proposals, engaging in legal proceedings to protect natural resources, and educating the public on local environmental issues.

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After each “weather event”, no matter how insignificant, there is a rush to judge the impact of the geotubes recently installed below Sankaty Bluff. If they remain intact, they are declared a success by some, while others express surprise that they have not been lost to the tides. The tubes’ own survival is not their purpose. Their success or failure can only be judged by their effect on the erosion of the bluff and the impact on the beach.

The winter weather during and after the installation of the tubes has not been a true test of the durability of the structure. Unremarkable tides, wind and rain have exposed the north end of the second tier of tubes, and one 24 hour period has seen the erosion of the beach to a point that appears to be near the top of the first tier. There has been no opportunity to evaluate the effectiveness of the tubes in protecting the toe of the bluff or to measure a potential loss of beach, but one thing is clear; the tubes will have no effect on the erosion of the bluff from above. Photos taken on the morning of 2/15/14 show significant new fissures in the face of the bluff and in the sand covering of the tubes. Large amounts of sediment have spread across the top and run down the south end and the front through crevices 2½ to 3 feet deep. Clumps from near the top have landed on the tube “deck”. Photos taken 24 hours later show new avalanches of dirt and several boulder-sized chunks, with much of the edge of the bluff looking ready to fall at any time. It would be fair to conclude that the bluff is eroding as quickly as ever from rain run-off and wind even if the tides are not reaching the toe.

We acknowledge that those with differing points of view will judge by different criteria. We feel that it can be called a success when it halts the erosion of the bluff and preserves the beach as well.

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We have a new folio titled What is There to Lose – The Future of Sankaty Beach. This folio contains photographs we have taken over the past five years. Our hope is that Baxter Road is soon moved and this beautiful beach can be restored to its natural state.

Click Here to View What is There to Lose.

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Twin Chimney has been moved to its new perch closer to Baxter Road.

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The geotube installation below the Sankaty Bluff is nearly complete. Work is being done to cover the tubes in the envelope of sand required to keep them intact. It is difficult to imagine that they can be kept covered without frequent replenishment, a job that will entail numerous heavy truck deliveries and one or more conveyor systems on Baxter Road for the duration of each recovering.

The photo below shows the second and third tiers of tubes prior to their first covering. It also shows that a less than extraordinary tide has washed away recently placed sand to a point similar to the face of the first exposed tube. This suggests that the maintenance will need to be more frequent than the proposed spring and fall replenishments, and more than the before and after storm maintenance that has been mentioned.

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Dirck and I have spent a great deal of time the past month covering the geotube installation on Sconset Beach. The tubes are now installed and work will begin covering them. Most of the sand allocated for this project will be used in covering the tubes. It will be interesting to see how much truck traffic this generates. Twin Chimney has not been moved onto its new foundation and Slip Slidin’ Away awaits its move to the lot next door. The photo below is of Slip Slidin’ Away. We have added a new slideshow to Nantucket Erosion. The link is listed below.

Click Here to View Latest Slideshow at Nantucket Erosion.
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A night of rain brought a significant amount of run-off from the top of Sankaty Bluff. Numerous rivulets of rainwater carried fine sediment down the face until it collected behind the second tier of geotubes. A wetland on the landward side of Baxter Road continues to drain under the road toward the bluff hours after the rain.

Click Here to View Latest Slideshow at Nantucket Erosion.

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We have a portfolio titled Feet of Clay – The Revelation of Sankaty Bluff that you can view here -

Click Here to View Slideshow – Feet of Clay.

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This photograph was taken yesterday as we were shooting the geotube installation on the beach below Sankaty Bluff. Our photos of the construction can be seen here – Nantucket Erosion.

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