Update on December 2023 NJDOT Rt 29 Rockfall Mitigation Working Group Meeting

Hi Friends and Neighbors,

The meeting topic was to discuss four options being proposed for area D the 2500’ stretch of RT 29 inclusive of the Devil’s Tea Table and surrounding scenic cliffs forest.

Some of us at the working group meeting found it a little discouraging but the process is continuing. 

What DOT proposed:

Option 1,  Mass Rock Removal- Includes defoliationand blasting away the entire cliff face including the Tea Table, all surrounding pinnacles and other natural features to create a new, very symmetrical stone cliff face.  This option met with intense disapproval by all on the call other than NJDOT staff and contractors.

Option 2, realigning the roadway– While this is something many of us on the call had advocated, we think the radical nature in which they proposed to do this is problematic for several reasons, including:

  • Incursion into the Delaware & Raritan State Park is extreme and likely not be permittable.
  • A 3000 ‘ + area from current route 29 to the river would be defoliated and the Rd moved 50’ closer to the river. The area currently is a natural river bank populate by healthy mature, native trees 50 to 80 feet tall and natural ground foliage.
  • A proposed 10′ high or more, by 3,000′ wide +- retaining wall would be built at the river’s edge and in the river much of the time.   We suspect the wall would affect river flow and would require an unlikely sign-off by the Army Corps of Engineers and other regulatory agencies.

Option 3, the shed – While looking something like a World War II artillery bunker in the photo they showed, it is probably the least destructive option, but still overkill and would be visibly and environmentally destructive.

Option 4, hybrid option.  This is the kind of thing they have preferred doing for some years.  It includes widespread defoliation, massive scaling, blasting to create large catchment ditch, chain rockfall fencing over much of the cliff face. This option also met with disapproval by all on the call other than NJDOT staff and contractors.

Below are excerpts from the Kingwood Twp working group representatives’ letter to NJDOT responding to options proposed:

We continue to believe that the extensive nature of all the NJDOT proposed mitigations will result in clear and dramatic damage to the sensitive and complex environment of the protected Wild and Scenic corridor along RT 29 in Kingwood, and any of the discussed alternatives should only be attempted following a full and independent environmental impact study process. In the best interest of this community, we hope NJDOT will support and request such a process be conducted.

“To better understand the current options presented we have some fact-finding questions.


  1. It remains unclear and concerning to our group why NJDOT will not consider using an 85% rockfall retention rate as is approvable by the Federal Highway Administration, especially in this case where there are no incidents of accidents or injury from rockfall along RT 29 in Kingwood Twp? 

This is especially concerning since there are few recorded incidents of rocks actually hitting the driving lanes even though NJDOT has been gathering data on this area since at least 1994. We request NJDOT evaluate all options we and DOT have advanced using an 85 % retention rate.

Who at NJDOT is responsible for setting or changing the retention rate target ?  Can they participate in these meetings? 

  1. Before we move any further in considering NJDOT options 2 or 3 for area D, can you please consult with NJDEP, the D&R Canal Commission, the Army Corps of Engineers, and any other involved entities to see if these concepts are at all feasible?”

“Kingwood Twp. community-suggested alternative mitigations for Area D:

  1. Install an electronic monitoring system as proposed by HNTB in 2015 for a 5 or 10-year test period to accurately gather a record of all rocks that actually hit the road. This would immediately enable road closure and NJDOT notification and rock removal in the event of a significant rockfall.  This would also enable NJDOT to propose future rockfall mitigations if needed based on actual rockfall data and not just hypothetical simulations.  This seems appropriate considering the sensitivity and importance of the area, the lack of accidents or injuries from rockfall on this scenic country road, the tremendous expense of all options proposed by NJDOT thus far, and the many other transportation safety projects that would provide higher benefit vs cost for a greater number of the people of NJ.
  1. Please design a less radical hybrid version of option 2 that includes: eliminating shoulders, reducing speed limit, moving the road less eastwardly, elevating the road slightly, including a small fence, using traffic signals to make this section one-way at a time, using a shock absorbing material in the catchment ditch to reduce rock fall bounce for our next meeting. 

Some or all of these steps could work to increase the retention scores and public safety with a much smaller catchment ditch and less incursion into the park and river.

  1. Please design a less radical hybrid version of option 3 – the shed – that includes only building a shed at two or three of the most at-risk sections of area D.

In closing, we unanimously believe that NJDOT holding fast to only considering alternatives that can obtain a computer simulation of 95% rockfall retention rates without carefully considering actual rockfall incidents and a lower retention rate is inappropriate for the RT 29 Kingwood Twp situation. It allows for consideration of only the most expensive, most destructive solutions that are clearly not in this community’s best interests.”

 We will keep you posted of the working groups progress.

All the best,


Stephen Freeman 

The Devil’s Tea Table Alliance  

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