Co-written w/ Ed Avizinis, CPSS, PWS | Avizinis Environmental Services avizinis.com
One frequent question we get, particularly for folks purchasing waterfront parcels is: Can I have a dock? We love docks, many of us in the office are boaters, surfers and sailors, and we recognize the benefits of having a dock. It is the Ocean State, after all. The answer to this question depends on a variety of factors that cover both regulatory and practical considerations. This blog post will walk you through our thought process and criteria to answer this question.
Step one is regulatory
Look at the CRMC Water Use Maps for your site.
If your property is adjacent to Category 1 Waters, you are unfortunately out of luck, unless you can petition CRMC for a change in the water use type, which is a very tall order. CRMC prohibits Docks in type 1 waters, as they are of high aesthetic, scenic and recreational value. If you’re adjacent to Category 2 or higher, your chances are generally good.
Often, this is the amount of “due diligence” folks put into a pre-purchase assessment, but let’s run through a more fine grained analysis of what it takes.
Water Use Maps: http://www.crmc.ri.gov/maps/maps_wateruse.html
Site Survey and Design Layout
One of the first things that we do is conduct a site and bathymetric survey for the property. We are trying to assess where can the dock go vs where the property line and property line extension (PLE) are.
The PLE, is generally, an imaginary line that is formed by extending the boundary sidelines toward the water. This, generally (unless there is a prior agreement or permit that delineates these otherwise). If your dock is set back more than 25’ from the PLE, you meet CRMC’s requirements. If not, you may need your abutters to sign off and apply for a variance.
What is the bathymetry (underwater contours) in the area of the proposed dock?
What we’re looking for here is to determine how long the dock needs to be to get to a reasonable depth. In most cases, we’re shooting for at least elevation -2 (vs. mean low water (MLW)), to satisfy minimal criteria for a float. If you have a sailboat with a keel, you may be looking for more depth. If you don’t have sufficient depth, there are some options, a fixed submerged pier, or a ladder off the end of the dock are common, though less desirable than a float. Typically, for single residences, floats of 150 sq ft are allowed prescriptively, though CRMC has provision to increase this size if residents propose a dock shared between two properties.
In terms of design, in most cases, we want to keep the dock length within prescriptive CRMC allowances, which is often 50’ from MLW (There are exceptions where longer docks are allowed, like the Sakonnet River). If we keep the dock at this length, there is a good chance of obtaining a permit. Longer lengths, particularly those requiring a variance need to be assessed on a case by case basis (note SAV section below).
We’ll also review the site’s CRMC file history. We want to ensure the upland elements are in conformance with prior permits, to avoid any issues with CRMC enforcement (they will check!) and to determine if there are any restrictions imposed on the potential dock or PLE from prior permits.
Wetlands and SubAqueous Vegetation (SAV)
An SAV survey is required for all residential dock applications. One primary concern of the CRMC is to ensure that the proposed dock will not impact beds of submerged aquatic vegetation (eelgrass or widgeon grass). These beds of submerged rooted grasses provide breeding ground for fish and crustaceans among many other species. These are significantly important nurseries for species all the way up the food chain and impact global fisheries markets. In the 1980’s, a disease specific to eelgrass, decimated SAV beds up and down the eastern seaboard. The populations are on a rebound now but remain threatened. As you can guess, these areas are highly regulated and monitored by CRMC.
CRMC has created some very general maps of known SAV beds. You can check to see if your area is mapped here.
This is not an absolute, but a guide. A site visit by a biologist (e.g. a professional wetland scientist (PWS)) is necessary to confirm or deny if SAV is present. Additionally, the biologist will map and flag the Coastal Feature (CF), as well as any coastal wetland that may require buffers or interfere with the dock or access.
BUT – do not let this dissuade you from pursuing a dock. There are many options that professionals can utilize to work around the eelgrass beds. We have permitted many many docks in waters with SAV beds and were able to avoid impact. Oftentimes the eelgrass bed exists in the shallower water and then ends where water gets deeper. This is one of the situations where CRMC will allow (and even encourage) a variance for a longer dock so the dock can completely span the SAV bed.
Going down the list, access is important, how are you going to get to the dock, both from a regulatory perspective and a practical one? Is there a view corridor and path, or is this an old site that’s pre-CRMP with no buffer? If you are limited with a view corridor and path, ensuring the dock can work in this location is key. In a perfect world, we’re able to design these elements in tandem, in case there are bathymetry or access limitations we can move the view corridor and path to suit, this is one of the reasons that comprehensive waterfront planning is crucial! If you already have a view corridor and path, but they are in a spot with poor bathymetry, it can be a real challenge to get these changed or request a variance to make the access for the dock work.
If you’re building a new house within CRMC regulated areas and or flood zones, refer to some of NEI’s other blog articles for more information.
Additionally, the height of the dock vs the heights of the grades matter – if there is a bluff or cliff, we may need to design steps, and we need to ensure that public access along the shore is not infringed upon by the dock. Which typically means providing at least 5’ of clearance underneath, or providing stairs on the sides of the dock so that passersby can walk over it.
Moorings can be an issue with Docks, typically these need to be separated by 50’ (to allow for moored vessels to swing around in the wind).
Moorings fall into two broad categories:
Riparian Moorings: these are moorings that are “owned” by the waterfront property owner.
Public Moorings: these are moorings that are placed by the municipality for residents, and generally managed by the harbormaster. Most municipalities have a GIS map or link that display these, regardless the harbor master should have this information “somewhere”…
Typically, we identify these as part of a site survey, and, if the harbormaster is willing, relocate these as part of the dock project. Riparian moorings generally cannot be moved, provided they are legal, but it stands to reason these should not exist within the site’s waterfront frontage.
Fetch is the distance wind can blow over water, to create waves. Docks that exist with a fetch of less than 4 miles, have no special consideration, “standard” construction practices will suffice. If a dock is in an area with a fetch of over 4 miles (for a 20 degree arc), special design considerations are necessary, and structural engineering and analysis is required to design the dock components (piers, stringers, connections, etc), to make the robust enough to withstand wind and wave loads. These docks, while feasible, generally carry a significantly higher design and construction cost.
The earth below the docks matters, since docks are set on piers, the density of the soil that the piers are embedded in matters. If the soil is soft (loose sand), larger or deeper piles may be required, conversely, if ledge (e.g. refusal) exists shallow enough to interfere with pile embedment, a more robust pile or a carbide pile tip may be required to anchor the pile. Again, while feasible, these piles require geotechnical engineering and carry a higher construction and design cost. Often doing a geotechnical boring is the only way to determine this information – although past projects, soils and surficial maps may act as a guide to identify sites where these constraints may exist.
Abutters can sometimes be problematic, as it relates to docks, all dock applications require public notification to abutters as part of the CRMC permit process. If an abutter has a valid concern, CRMC has to take it seriously and may require the dock application to proceed to CRMC Council for approval, as opposed to an administrative permit that does not require a hearing.
Navigability and Army Corps
Residential docks, and their approaches, cannot interfere with designated shipping channels; NOAA maps display these, and while rarely an issue, it needs to be checked during the design.
All dock permits are required to be filed with US Army Corps of Engineers (USACOE).
This is just a cursory run through the factors that matter when planning a dock – the reality can often be more complex, and good reason why a call to our office is generally the best first step. We have staff with decades of experience in these areas, as well as specialty consultants we can tap for assistance when needed for atypical design considerations.
The link below is CRMC’s Dock and Pier checklist, and neatly categorizes many of the key requirements when applying for a permit. NEI generally writes an accompanying narrative to the plan to answer these questions, so that we can ensure that your permit is obtained as expeditiously as possible.
Dock Pier Checklist: https://crmc.ri.gov/applicationforms/DockPier.pdf
Please don’t hesitate to call, or email, if you are considering a dock!