The Pecos River is not usually much more than a damp ditch, it does meet the statutory definition of navigable in the State of Texas. We have to determine the area of the river bed that is public lands but with all the rain we've had lately, it's been a tough job. Plus all the salt cedars, the steep banks. Heck, it's a real pain to meander the river.
But thank goodness we're done with that. Apparently someone in the GLO Minerals office came up with a new method for determining area of the river bed. They are running a polyline down the middle of the river on their GIS software and then offsetting the line 15 feet on either side (30 feet being the minimum width of statutory navigability). Trim the polygon by projecting the GIS section lines and we are done! No need to get a crew out, no waiting for flood conditions to end. All from the comfort of the GIS at your office with our increasingly infamous "Original Texas Land Surveys" shapefile.
Thank god the staff at the GLO Minerals office are looking out for the public interests.
> The Pecos River is not usually much more than a damp ditch, it does meet the statutory definition of navigable in the State of Texas. We have to determine the area of the river bed that is public lands but with all the rain we've had lately, it's been a tough job. Plus all the salt cedars, the steep banks. Heck, it's a real pain to meander the river.
>
> Apparently someone in the GLO Minerals office came up with a new method for determining area of the river bed. They are running a polyline down the middle of the river on their GIS software and then offsetting the line 15 feet on either side (30 feet being the minimum width of statutory navigability). Trim the polygon by projecting the GIS section lines and we are done! No need to get a crew out, no waiting for flood conditions to end. All from the comfort of the GIS at your office with our increasingly infamous "Original Texas Land Surveys" shapefile.
>
> Thank god the staff at the GLO Minerals office are looking out for the public interests.
Actually, I'd think a very rational approach to that problem would be to measure between the gradient boundaries at intervals and take an average for a particular reach of the Pecos. Applying that width to either side of centerline of the channel as may be digitized from an aerial photo is a good, practical solution in my view.
That method:
(a) preserves the State's interest in the bed in that it represents an area that is is based upon actual measured widths and so is good estimate and
(b) doesn't waste time on delineating a boundary that no two surveyorss will be able to duplicate and that over time will shift position even if they did.
An upland owner of a survey that was patented on field notes crossing the Pecos River can still argue that the bed was relinquished to them. If only a part of the bed was relinquished, the above method is an extremely practical way to partition the bed between the State and upland owner.
A very similar problem would be encountered trying to surveying along the Rio Grande above Presidio, where the actual river is completely overgrown in salt cedar so thick a dog couldn't crawl through it and the river itself is an floatable trickle of a creek full of snags other than from those rare times when it floods. There, the centerline of the river can be located fairly readily, either from aerial imagery or by GPS from a boat when the river is up during one of the few times when it can be navigated.
The banks? The channel is regular enough that it really doesn't matter for area computation where it is as long as the average distance from the centerline is a good value.
The 30' method is what they had us do about a year ago, we meandered one "bank", but then they said to split 15-15 on the c/l from an aerial, not theirs necessarily, but an aerial.
They were a little late on the suggestion. We finished the river work today.
Determining the average width in the vicinity of the actual survey seems more prudent to me than just using 30 feet.
> The 30' method is what they had us do about a year ago, we meandered one "bank", but then they said to split 15-15 on the c/l from an aerial, not theirs necessarily, but an aerial.
Well, that's an easy way to guarantee that at least some Permanent School Fund land shows up in the mineral leasing picture. The thirty foot wide channel sounds like more of an easy placeholder than anything.
The Rio Grande is the International border, and as such is not subject to normal law. The US and Mexican sections of the International Boundary and Water Commission must jointly agree where the thread of the river is. Once the agreement is made it doesn't move until a new agreement is agreed to. These agreements are made at set intervals of time and significant accretion and erosion can occur between updates. At any particular time the North bank could be in Mexico.
The section at issue was in the vicinity of Candelaria in Presidio County where channelization had occurred. While there were various bancos in the vicinity (relict bends where the river had shifted since the original treaty), none of them really came into play in the problem, which was to identify the boundary of various land grants made by the State of Texas on corrected field notes following a resurvey made in 1886 by Murray Harris for the Texas & Pacific Railroad Company (my best recollection without actually checking the file).
What the International Boundary Commission had done in the vicinity of Candelaria was to make an absolute, incredible mess of pretty much everything. There were lots of IBC monuments (probably from the 1920's or 30's) on the high terraces above the river and there was absolutely no one in the IBC offices in El Paso who claimed to know the slightest thing about them. This was about twenty years ago, so it is possible that some extremely diligent and competent folks have come to work at the IBC who have managed to figure out which dumpster their files actually went into.