Leander Elite Concrete works as a concrete contractor in Bee Cave, TX, building patios, driveways, walks, slabs and pool decks with more than 20 years of experience on Hill Country ground. On a creekside lot here, the first question is not what the client wants built. It is how close to the creek anything is allowed to go.
The Unified Development Code sets water quality buffer zones that operate as hard setbacks on flatwork, and the width depends on which creek the water eventually reaches. Some lots carry an 85-foot buffer on each side of a waterway; others carry 300 feet.
That is a very large difference, and it is decided by drainage rather than by appearance. Two creeks that look alike from a back yard can carry buffers more than three times apart, so establishing which one applies is the first thing we do on any lot with water on or near it.
Eighty-Five Feet or Three Hundred, by Which Creek You Drain To
The Upland Waterway Buffer
UDC Section 7.3.2.C.5 sets a minimum buffer of 85 feet from the outer limit of the peak two-year flood level, on each side of an upland waterway with at least 30 acres of contributing drainage. The code defines an upland waterway as a defined waterway that is a tributary to Little Barton Creek, Barton Creek, or the Colorado River.
The contributing drainage threshold matters as much as the width. A small drainage line with less than 30 acres behind it is not an upland waterway for this purpose, so establishing the contributing area is part of determining whether the buffer applies at all. We work that out before designing rather than assuming from the size of the channel.
A modest-looking swale can carry a substantial catchment, and a wide-looking wash can carry very little. Contributing drainage is a mapped and calculated quantity rather than something read off the ground, and the 30-acre figure is close enough to ordinary suburban catchments that it genuinely decides cases either way.
The Three Hundred Foot Buffer
On Little Barton Creek and Barton Creek themselves, the minimum buffer is 300 feet on each side. That is a scale of setback that removes a great deal of a typical lot from consideration for any impervious construction.
Where a property carries that buffer, the design conversation changes completely. Rather than deciding how large a patio should be, the question becomes where on the lot a patio can exist at all, and the answer is frequently much closer to the house than the client pictured. We establish which waterway a lot drains to at the very start, because the difference between 85 and 300 feet reorganizes an entire design.
That determination is made from the drainage rather than from what the water looks like on the ground. A tributary that reaches Barton Creek carries the wider protection even where the channel on your lot is small, because the buffer follows what the water eventually feeds rather than the size of the feature in front of you.
The Watershed Divide Through the City
The city straddles a watershed divide, which is why both buffer widths occur here and why the answer genuinely varies by address. Bee Cave also sits substantially inside the Edwards Aquifer Contributing Zone: of 85 systematically spaced interior points, 71 returned that zone and 14 returned none, with the in-zone points running from latitude 30.29134 to 30.32312, so the zone boundary crosses the city rather than enclosing it. No point returned recharge or transition zone.
That boundary crossing the city is exactly why we check a specific address rather than generalizing. Two properties a short distance apart can sit on opposite sides of a mapped line, and the applicable requirements follow the line rather than the neighborhood.
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Measuring From the Two-Year Flood Level, Not the Bank
An Unusual Starting Point
The buffer is measured from the outer limit of the peak two-year flood level rather than from the top of the bank or the edge of the water. That is a hydrological reference rather than a visible one, and it can sit well back from anything a person would identify as the creek.
The practical consequence is that a buffer measured from the bank understates the setback, sometimes considerably. A design laid out that way looks compliant on a sketch and is not. We take the measurement from where the code takes it and work with the client’s surveyor or engineer when the flood level has to be established.
It is not a dimension that can responsibly be estimated on site. Where a client has already had survey or engineering work done for another purpose, that information frequently answers the question, which is why we ask what exists before commissioning anything new.
Why the Reference Point Was Chosen
Measuring from a flood level rather than a bank ties the protection to how the waterway actually behaves rather than to where its channel happens to sit today. Channels migrate; the area a creek floods is a better description of the ground that matters. For a flatwork designer that means the buffer edge is a line on a drawing rather than a feature you can walk to. We treat it as a survey line and set it out accordingly before forming anything.
What a Buffer Means for a Patio
Inside the buffer, impervious construction is not something a design negotiates around. That makes the buffer edge the effective property line for planning purposes, and everything the client wants has to fit between the house and that line. We map the usable envelope first and design into it. That approach almost always produces a better result than designing what the client asked for and then cutting it back, because the shape of the available area usually suggests a different and better layout.
Critical Environmental Features and the Hundred and Fifty Foot Ring
What Counts as a Critical Environmental Feature
Critical environmental features under the UDC expressly include steep slopes in excess of twenty-five percent, groundwater recharge areas, springs, wetlands, bluffs and caves. A bluff is defined as a vertical change in elevation of more than 40 feet at an average gradient greater than 400 percent.
A critical environmental feature buffer zone extends a minimum of 150 feet around the feature. That is a second, independent set of buffers that can apply on the same lot as a waterway buffer. Steep slope is the one most often overlooked, because it is a property of the ground rather than a feature you can point at.
On Hill Country lots, a slope over twenty-five percent is common enough that it is worth checking rather than assuming. A quarter grade is steeper than most people estimate by eye, and a bank that reads as a gentle fall from the house can cross the threshold over part of its length.
Buffers That Overlap
Where more than one buffer applies, they do not cancel out or average; each applies on its own terms. A lot with a waterway on one side and a steep slope on another can have its buildable envelope constrained from two directions at once. We draw them all before designing. A layout that satisfies one buffer and ignores the other is a layout that gets discovered late, and by then the design work has already been done twice.
Establishing What Is Actually on the Lot
Some features are obvious and some are not. A spring, a cave or a recharge area may be identified in existing documentation, or it may need looking for, and a steep slope has to be measured rather than judged. We ask what is known about the property and look at the ground carefully before committing to a design. It is a short exercise compared with the cost of laying out a patio in a place it cannot be built.
What Is Left to Build On Once the Buffers Are Drawn
Designing Into the Envelope
Once the buffers are mapped, what remains is the real site. On many lots here it is considerably smaller than the deed area suggests, and it is often an awkward shape rather than a neat rectangle. We treat that envelope as the design brief rather than as a limitation on one. Working with a constrained shape from the beginning tends to produce layouts that feel deliberate, whereas trimming a rectangle to fit produces something that reads as compromised.
Getting More Out of Less Area
Where the available area is limited, the useful moves are about quality rather than quantity: better finish, considered levels, a well-designed transition from the house, and features positioned where they will actually be used. We would rather build a smaller patio properly than argue for a larger one that cannot be permitted. A retaining wall greater than 4 feet in height requires a city permit, as does major dirt disturbance, and a deck exceeding 200 square feet or standing more than 30 inches above grade requires one too, so the supporting works have their own approvals to plan around.
Working on a Constrained Site
Bee Cave is a city in Travis County whose population was 9,144 as of the 2020 census, and on lots of the size and terrain common here, access and staging are frequently as constrained as the building envelope itself. We plan material delivery, spoil removal and equipment access alongside the design rather than after it. On a lot where the usable ground is limited by buffers, there is often nowhere convenient to put anything, and that has to be solved on paper rather than on the first morning.
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