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Mean High Water Line

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Mean High Water Line

Posted by rbcslim on Dec 14, 2010 10:58 pm

I am in North Carolina trying to establish the boundaries of an upland owner who adjoins a navigable, tidal river. My research has lead me to the facts that the mean high water line is the boundary between my client and the public(state) ownership of the river, and that this mean high water line is determined by the arithmetic mean of the high water heights observed or a 18.6 year epoch. The recorded previous survey of the land runs the lines well out into the rivers water and is well past the apparent visible high water mark which is marked by the base of a 60' cliff where the beach ends and the vegetation begins to grow up the cliff. Recent adjoining surveys run their lines even further into the water. So my question is how do many of you approach determining a similar boundary? Do you survey to the apparent physical evidence of the high water mark(and maybe label it on your plats as the "approximate" high water line, or do you actually locate this 18.6 year data and determine elevations to establish the line, and if so, where would that data be obtained?
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Re: Mean High Water Line

Posted by Casimir on Dec 15, 2010 6:30 am

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Re: Mean High Water Line

Posted by Rusty Chain on Dec 15, 2010 1:46 pm

In my state, for any tidally influenced waters, we generally determine the mean high tide line as you describe (go to the tides and currents site provided in the previous post).  But check your state laws and cases in your jurisdiction to see if it is more appropriate to rely on the vegetation or a scour line.  This is one of those areas where the science is pretty universal, but use of it is not between jurisdictions.

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Re: Mean High Water Line

Posted by Don Poole on Dec 15, 2010 3:16 pm

It depends on the purpose of the survey. 
Many, around here, will use vegetation lines, or obeserved high watermarks for local permitting. 

For property lines, I use the data collected from NOAA at various point around the Cape.  I prefer using an elevation since that has been deteremind by constant observation during the pervious diurnal cycle and is something that any one of us can reproduce on the ground.  

MA is different than where you are located.  Our private owernship runs to MLLW or "100 rods" whichever comes first.  However the property lines of the "flats" are not just extensions of the upland lines but must run "normal " to the shore so as to preserve water frontage for all those that have is at high tide.  Proportional divisiol of the flats is an iteresting subject!!


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Re: Mean High Water Line

Posted by walt dunlap on Dec 15, 2010 5:15 pm

Rusty is right; there may be strong local evidence of MHW indicated by vegetation. A new York case acknowledged this as the boundary between
two types of shoreland grasses: spartina patens and spartina alterniflora, if memory serves. The thinking being that these grasses, where present, establish themselves over a long enough period of tidal action to be as indicative as any man-derived tidal benchmark data of the MHW. Ownership beyond that may exist or not and may have been conveyed out or not, with the presumption in Colonial rule states being to the MLW or 100 rod limit.
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Re: Mean High Water Line

Posted by Jered McGrath PLS on Dec 15, 2010 5:48 pm

Chapter VIII of the new BLM manual has probably all the information you need. Besides any local state ruling that may dictate a "special circumstance"

"...for lands fronting tidal water, the intention is that the ownership extends to the line of mean high tide, MHT. However meander lines may become fixed and limiting boundaries" under special circumstances described in....."
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Re: Mean High Water Line

Posted by Rusty Chain on Dec 16, 2010 1:28 pm

Good point, Mr. McGrath.  States (my state anyway) will sometimes enter into boundary line agreements with upland owners to fix a line to define the limits between upland ownership and the state's soveriegn lands of tidelands or the bed of the body of water (depending upon which body of water).  This generally occurs where man-made influence is precluding or significantly altering the natural action of the tides and/or wave actions upon a beach or other waterfront.  BLAs are not common where there is no significant man-made alterations to the waterfront or where there are no dikes, piers, jetties, or groins in the vicinity which may have an effect on the natural movement of beach material by tides or wave action.

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Re: Mean High Water Line

Posted by JBStahl on Dec 16, 2010 2:21 pm



You have to be careful that you don't mix separate bags of tricks when talking about riparian, littoral, and tidal boundaries.  Water boundaries are tied to "physical" features (boundaries are physical objects).  That's why the vegetation and physical escarpments are the key to determinng the boundary location.  The tidal elevations (determined by the 18.6 year cycle) have nothing to do with (or, "should" have nothing to do with) the location of the boundary.  The concept of water boundaries are too often mixed up with the concepts of water elevations at various stages.  Stick with the physical features to determine the boundary.

The "mean high water 'line'" is a physical "line," not an elevation.

JBS


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***May your Boundaries Fall in Pleasant Places*** Ps. 16:6
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Re: Mean High Water Line >>JBS

Posted by Don Poole on Dec 16, 2010 2:33 pm

I couldn't disagree with you more, John.

Working in one of the few remaining states where ownership extends "as far as the ebb shall flow" or 100 Rods, and having had a few projects requiring deteminatino of ownership below Mean High Water, I can state that the elevation observed over 18.6 years does contorl property boundaries in MA.

If I recall, the last time we "spoke" about this you referenced a MA case that I was invovled in and the court agreed with my methodology of MHW location, and it was upheld on appeal.

The high water mark changes daily, withthe tides and winds, seasons, etc...the elveation may change, and it's location on the ground may change with time, but an elevation is something that we can all place on the ground.   Any other method is subjective and is arguable before any permitting boards.


Mean High Water is an established elevation,  High Water Mark is an observed feature and will not control property lines in MA.... 

>>


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Re: Mean High Water Line

Posted by Rusty Chain on Dec 16, 2010 6:18 pm

I also disagree with you, John.  There will be locations where the vegetation or scour line is the best evidence, but there will be many locations where the MHTL is the only viable evidence.

If we were to go by the vegetation line and ignore the MHTL, several billion dollars worth of what has been considered private upland along the CA coast would be reclassified as State property with several billion dollars worth of encroachments on it.  On the coasts, storm events will often push the vegetation and scour lines far above the MHTL, thus they are often very poor indicators of the MHW.

In riparian situations, along inland lakes and waterways, the vegetation and/or scour are often the best indicators.  But be careful with that as well.  If dams, canals, or other diversions have changed the natural course or extent of the river or lake bed, current vegetative or scour lines may be of little use.  States (western ones anyway) gained sovereign title to the beds of navigable waterways at the time of statehood.  If the flow diversions were built after that time, the state will determine the location and extent of the bed where it last naturally existed to stake their claim.

Tidally influenced waterways such asbays, inlets, and the lower reaches of rivers are gray areas (sometimes literally as well as figuratively) where both MHTL and vegetation/scour lines must be considered.  These are the areas where you are most likely to find different jurisdictions dealing with the littoral/riparian boundaries differently.

Since Utah has very little coast line, we'll cut you a little slack this time John.  ;-)

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Re: Mean High Water Line

Posted by JBStahl on Dec 16, 2010 10:09 pm


Perhaps (obviously), I should clarify...  ;o)

I agree, Don, that "mean high water" is an elevation.  The "mean high water line, however, is a physical feature.  

So, if I'm understanding the dissension here, those who are relying upon elevations are tying their survey datum to a known benchmark, then performing a topographic survey to determine the contour elevation line locations, then staking a contour line?

I do have some hesitation understanding how the 100 Rod line is tied to an elevation.  Is the 100 Rods is tied to the MHWL (a physical feature), or a contour line? 

JBS

PS  Storm events are a whole different ballgame as they are avulsive events.  Another bag of tricks.

PSS  Thanks for the slack, Rusty.  Utah's Great Salt Lake does have about 10000 miles of shoreline.  It's just all pointed inward instead of outward.  The state has been unsuccessfully arguing "elevation" of the GSL with the Utah Supreme Court for over a century.  The USC keeps pointing to the HWL that's not there either.


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Re: Mean High Water Line> A line is just a line

Posted by Don Poole on Dec 17, 2010 8:19 am

a line is just a line until it's given definition.    MHW is an established term that has a legal definition, I assume we can agree on that?   High Water Mark (as we use it around here) is the observable evidence of the last highest tide, as well as any lower tides since the last higer one.

Each of them are a "line" on the ground.  MHW line, or High Water Mark line.   One is by elevation the other by observation. 

Your outline of the process; Topo, Determine MHW elevation, then stake a contour is correct.  (By the way several towns use the flood plain contours as zoning lines for setback purposes.)

How is the 100' Rods tied to an elevation?  "Ordinary low water mark " means Mean". Mass. 1909 East Boston Co v. Commonwealth 89 NE 236,  203 MA 68.17  Ann.Cas 146.....
Conversly Ordinary Mean High Water MARK means "Mean."   

One of the difficulty's in using a high water mark as your boundary is that there are several to choose from at any given time.  Shall you just pick the one in the middle?  Without an elevation how can you figure which mark is ordinary or normal, or the Mean?

In Eastham, John, the horizontal distance between high water marks can be 20'-30' or more.  The slopes on the flats are so gradual that the last high tide will leave a "wrack" line, as has each previous higher tide, wind driven, normal, still water, what ever!!!  so we walk out there, do cross sections, tie in to known benchmarks and interpolate the elevation of MHW at the site.  That is something that we can hang our hats on, testify to, and not have to defend the disappearing evidence that the last storm tide blew out....

Would you like a picture ?

Don

 

PS   By the way, we have a ten foot tide here in Cape Cod Bay.....The flats, at low tide, can extend out for a mile out at low  water.


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Re: Mean High Water Line

Posted by JBStahl on Dec 17, 2010 11:09 am


Don said, "One of the difficulty's in using a high water mark as your boundary is that there are several to choose from at any given time.  Shall you just pick the one in the middle?  Without an elevation how can you figure which mark is ordinary or normal, or the Mean?"


That's my point, exactly, Don.  The elevation can be used to select which physical mark on the ground is the correct mark, or it could be used to fill in where the mark has been obliterated.  However, the elevation or the contour are not the mark; they are evidence which can be relied upon to determine the physical mark.  The elevation isn't the boundary, and the contour isn't the boundary.  The mark is the boundary.

Don said, "The slopes on the flats are so gradual that the last high tide will leave a "wrack" line, as has each previous higher tide, wind driven, normal, still water, what ever!!!  so we walk out there, do cross sections, tie in to known benchmarks and interpolate the elevation of MHW at the site.  That is something that we can hang our hats on, testify to, and not have to defend the disappearing evidence that the last storm tide blew out...."

The dynamic nature of the HWM makes the determination quite difficult along flat or exposed shorelines, that's for certain.  We deal with lake shores where a few inches of rise in elevation can inundate miles of land leaving false features as you noted.  Those same dynamics also change the boundary daily, monthly, yearly, or over decades.  I think we have a tendency to "hang our hats" on something we can measure (elevations) rather than something we can see (the physical markings) because we can see the marks change, but can't see change of an invisible contour line.  Truth is, the contour line is changing as well, there's just no physical evidence to prove that it did, except when we have two or three surveys over time to compare. 

I'd still hang my hat on the physical evidence corroborated by evidence of tidal actions, including elevations.  IMHO, holding an elevation only would be akin to declaring the HW Mark "lost" (no remaining evidence) and applying the "rule of last resort."  Sometimes the last resort rule is applicable, but only as a last resort.

JBS


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Re: Mean High Water Line

Posted by Don Poole on Dec 17, 2010 12:13 pm

The high water mark is simialr to a stone bound that someone keeps moving around twice a day.  You will use bearings and distances to repalce the bound, and the bearings and distances may not be the "bound" but the best evidence to locate it in it's "correct" location.

This is the same as replacating  Mean High Water by elevation.   The marks left by the previous tides are simply guidelines, not unlike blazed trees, but to get Mean High Water located you have touse an elevation...


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Re: Mean High Water Line

Posted by JBStahl on Dec 17, 2010 12:35 pm



"The high water mark is simialr to a stone bound that someone keeps moving around twice a day.  You will use bearings and distances to repalce the bound, and the bearings and distances may not be the "bound" but the best evidence to locate it in it's "correct" location."

Whoa, time out there, Don...  are you saying that tidal boundaries are not dynamic?  That they are fixed in location?  If so, at what moment in time were they fixed?  How do you determine which contour is the "correct" one?  I agree that "the high water mark is similar to a stone bound" and that it "keeps moving around," but how can a bearing and distance control over a natural monument?  Are you saying that if two surveys were done on the same day, they'd both be "correct" but in different locations?  Or, are you saying that the bearing and distance from some prior survey would control a fixed line?  What day does the line become fixed?  How does the contour become fixed in location if the elevation of the shoreline is changing?

"to get Mean High Water located you have touse an elevation..."

Yes, Mean High Water is defined by the elevation, however the Mean High Water Mark is determined by the physical features caused by the consistent action of the water while it occupies the Mean High Water elevation.  The distinction seems trivial, however, the outcome is quite different at times.  Knowing the MHW elevation is important for the reason that it can lead you to the area where the physical evidence (the natural monument) exists.  The elevation gets you into the search area, just as a bearing or distance would.  Once you're in the area, that's where the search for the monument begins.  I will agree that at certain times under certain conditions, the monument may be obliterated making its recovery difficult.  Sometimes, the monument is completely lost.  That's the point where one would rely upon elevation to determine the MHWM by applying the rule of last resort (ie. measurements).

JBS


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Re: Mean High Water Line

Posted by Rusty Chain on Dec 17, 2010 1:31 pm

Good description, Don.

John,
Yes, the MHW Mark, if it exists at all is constantly changing along a coast.  That is why the MHTL becomes the best indicator.  I agree with your analogy to a lost corner, but disagree with the parallel with an upland corner. (I guess it was Don who first made the analogy and parallel).

An upland corner should never move from its original location.  The nature of upland boundaries is very different and must be thought of differently.  More often than not, there is physical evidence remaining for upland corners and rarely a need to resort to something like proportionate measure (the mathmagical solution).  A riparian or littoral boundary is ambulatory.  It is constantly moving to one degree or another.  In some cases, lakes or slow moving waterways, the change may be imperceptible over many years.  The physical indications of the high water mark are far more likely present and most often far better evidence than an elevation in such cases.  Along a sand beach on open coast, a difference may be measured from one day to the next, certainly from one month to the next.

Because of the effect of storms, which occur with great regularity along coastlines, the storm driven wave action has a tendency to not let vegetation even get a foothold near the MHWM in many locations.  This is not considered avulsive and is different from a storm event which may cause an avulsive event upland.  In a river farther inland, an avulsive event will generally only occur when an extraordinary amount of precipitation or snowmelt occurs in a short time period causing unusually high flows, a relatively uncommon storm.  On the coast, regular wind and wave action from more common storms beat back the vegetation, and sometimes create a false bank well above the MHTL, or ordinary high water.  Often, the surveyor is looking at a broad sand beach or mud flat that offers no definitive mark beyond the "wet sand" line made by the last few waves to hit the shore and not at all indicative of a HWM. 

If you go to Google Earth and look up "Malibu Cove Colony Dr, Malibu, CA", you will see an area where about $200M worth of homes are built partially seaward of the edge of vegetation/toe of upland slope and out onto the sand beach.  You will also see a "wet sand line" roughly at the seaward edge of or just a few feet seaward of most of these homes.  This is one example, similar situations can be found up and down the coast throughout the state.

Take a look here for an oblique view of the same area: http://www.californiacoastline.org/cgi-bin/image.cgi?image=200601773&mode=sequential&flags=0&year=2006


By elevation, based upon the tide station at Santa Monica, a few miles east, the MHTL is still a few weet seaward of the wet sand line in that image.  The level of the tides almost never reaches that toe of slope which is under the houses.  It cannot be considered an ordinary high water mark.  But the wave action from seasonal storms does reach that point, perhaps several times a year.  A storm event is not an ordinary occurrence with respect to determining Ordinary High Water, so the mark left by storm events cannot be considered to be the Ordinary High Water Mark.

The farther inland one goes along an inlet or river, the less elevation of the MHTL will influence the determination, and the more physical marks will do so.  It depends upon the specific characteristics of the waterway, the adjacent upland, and the treatment the courts in that jurisdiction have given such cases, if such cases have been heard by appellate or supreme courst in those jurisdictions.

With the Great Salt Lake, being an inland, non tidal water body, I would think that the physical marks would be better than some elevation assigned.  However, elevation is often the determinate factor along the shores of impoundments.  Lake Tahoe has become sort of a hybrid.  It is a natural lake that had a dam placed across its only outlet.  By a water rights settlement and by court ruling, its boundaries are now defined by elevation.

There are a few good references on the subject.  The BLM manual tells us how the feds address it, but that may be very different than how the states address it.  A good reference, particularly for CA but with applications elsewhere, is Water Boundaries, Demystifying Land Boundaries Adjacent to Tidal or Navigable Waters by Bruce Flushman.  The first exhaustive reference, which is now out of print but still authoritative, is Shore and Sea Boundaries by Shalowitz, published by the USC&GS.  Don may have more suggestions applicable to the Eastern States.  This 100 rod thing is a foriegn concept to me.

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Re: Mean High Water Line

Posted by Don Poole on Dec 17, 2010 2:00 pm

John, I think you missed my point about the stone bound etc....  The water mark moves with the tides, twice a day, the MHW elevation will change but more slowly over time, and in accordance with the diurnal cycle.  With the exception of storm events that will change the ground features dramatically.  However, the Elevation of MHW will remain the "same" qand can be reproduced EVEN IF a reliable high water mark isn not evident.

So, suppose that a survey is completed and a stone bound is located for a property corner.  Someone comes and moves that bound twice a day;  Where is the corner now and how do you reproduce it?  Bearings and distances from other known bounds, I hope?

If I do a survey on the shore and locate the MHW by elevation, as well as the high water marks, I accept that those high water marks will be in a different location tomorrow.  Where is the boundary now?   
Furthermore, I have a shell fisherman that wants to place an aquacultrure grant about 500' out on the flats but since the grant is given by the town it has to be on town property, not private.  I can reproduce the MHW elevation for the upland boundary and then apportion out the flats to determine where, 500' out there, his grant can lie.   That MHW elevations may change, gradually over time, and theupland location of MHW may change, again gradually over time, but they can always be reproduced.   the difference being that the elevation may change, but gradually, whereas the high mark moves twice a day.  I've noticed then where i've been duck hunting lately, the wrack line has been all over the place!

I would reference Frankel's Shore and Water Rights, and Coles, Water Boundaries for east coast applications.   Frankels is very good as it applies specifically to MA and ME shorefronts.


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Re: Mean High Water Line

Posted by JBStahl on Dec 17, 2010 6:01 pm



Excellent responses, both Rusty and Don.

Note to Don, however...  You seem to speak of the HWM as being defined by the "drift" line or, as you put it in an earlier post, the "wrack" line.  Isn't that the limit of the floating debris left on the shore by the receding tide?  If so, that's not what I would call the High Water Mark.  The HWM is, simply, a natural boundary and it is dynamic in nature.  The mark is not found at the furthest extent of the driftwood or debris which happened to be deposited on the highest wave or by some errant storm.  The mark should be more evident from what is typically found as a change in vegetation or an escarpment created by the persistence of the MHT action over time.  Of course, the flatter the shore, the more dynamic the inundation of the wave actions are, and the further upland the HWM may appear to be driven.  That's where knowing the local conditions (including the elevation of the MHT) could be used as an aide to determine the actual HWM vs. the apparent HWM (as in Rusty's link).  In that, I think we are in agreement.

I also have trouble with your analogy of an upland stone bound being moved.  That doesn't equate at all in my mind to an ambulatory natural boundary which is expected to change in location over time.  The boundary, however, remains the same (it's still the HWM).

JBS


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Re: Mean High Water Line

Posted by Don Poole on Dec 18, 2010 11:21 am

John,  The mark that you refer to is quite elusive in the flats where I work.   Some other areas there may be a stain on boulders or pilings, but that would be in a less dynamic area than Cape Cod Bay.  With a 10' tide we get about 1.5' per hour vertical movement of the water and that leaves little time for staining.  Vegatation lines are good for permitting purposes because that is very site dependant and indicates current conditions, without taking the diurnal cycle into account.

Happy Holidays to you and your family.  We are tree trimming today!

Don



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Outermost Land Survey, Inc.

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