Ono Island Waterfront & Boating Guide

Reading the Water: What Tidal Benchmarks Mean for Ono Island Buyers and Boaters

A practical look at tidal datums, waterfront elevations, dock depth and the quiet measurements behind life near Perdido Pass.

There is something wonderfully simple about watching the water around Ono Island. The tide rises against a pier. A boat rocks gently on its lift. Sunlight stretches across Bayou St. John, Old River and the Intracoastal Waterway. Yet beneath that beautiful scene is a surprisingly precise system of measurements—one that can matter when purchasing waterfront property, evaluating a dock or planning a coastal home.

Near Perdido Pass, NOAA established a series of tidal benchmarks at Alabama Point. These small survey disks may not look particularly remarkable, but they connect recorded water levels to fixed points on land. In practical terms, they help surveyors, engineers, scientists and coastal professionals speak the same language when discussing water elevation.

As an Ono Island homeowner and local real estate advisor, I believe waterfront buyers should understand at least the basics of that language. You do not need to become a surveyor or marine engineer. You simply need to know which questions to ask—and when a casual observation from the dock is not enough.

“A waterfront property should be evaluated from both directions: from the street looking toward the house and from the water looking back toward the dock.”

Meredith’s Waterfront Perspective

What Is a Tidal Benchmark?

A tidal benchmark is a permanent marker installed on stable land near a water-level station. NOAA uses these fixed markers to preserve the relationship between the land and the different water elevations measured at that location.

The published Alabama Point benchmark sheet identifies NOAA Station 8730667 at Perdido Pass. The document describes five benchmark disks placed in and around the concrete seawall, helicopter pad and porch near the Alabama Marine Police property. The original gauge and tide staff were located on a nearby pier.

These markers are not simply high-tide signs. They are recoverable survey references. A qualified professional can use a verified benchmark or another approved control point to relate an elevation on land to a recognized vertical datum.

What Do MLLW, MHW and MHHW Mean?

Tide reports, surveys, marine plans and elevation documents may use several abbreviations. They sound technical, but the general ideas are fairly approachable.

NOAA cautions that NAVD88 is not simply another name for local mean sea level. Each datum must be identified correctly. When reviewing an elevation, I always want to know the reference datum, because a number without its reference point can be misleading.

What the Historical Alabama Point Record Shows

The NOAA benchmark sheet supplied for Alabama Point was published in 2003. Its tidal datums were developed from a four-month observation series extending from December 1993 through March 1994 and were related to the Pensacola control tide station.

These figures summarize the historical station record in the supplied benchmark sheet. They should not be substituted for a current survey, current tide prediction, site-specific depth measurement, elevation certificate, engineering determination or permitting requirement.

Does This Tell Me How Deep the Water Is at an Ono Island Dock?

No—and this is one of the most important distinctions for a waterfront buyer.

The Alabama Point station provides a regional tidal reference near Perdido Pass. It does not tell us the present water depth at a private pier on an Ono Island canal, Old River, Bayou St. John or the Intracoastal Waterway. Local depth can be affected by the specific waterway, distance from the channel, shoaling, dredging history, sediment movement, dock configuration, wind and recent weather.

If boating access matters to a purchase, I recommend measuring the depth at the dock and along the intended exit route under realistic conditions. Whenever possible, I like the evaluation to include a lower-water period and the actual type of boat the buyer plans to keep.

Tide Height and Tidal Current Are Not the Same Thing

This distinction is especially important around Perdido Pass. Tide predictions describe the expected time and height of the water. Current predictions describe the expected direction and speed of moving water, including flood, ebb and slack periods.

High tide does not automatically mean slack current. NOAA explains that the relationship between tide height and current timing is unique to each location. Boaters should consult the appropriate tide and current information separately rather than relying on a general rule of thumb.

Predicted tides also represent astronomical conditions. Wind, rain, freshwater runoff and other weather influences can cause observed water levels to differ from predictions. Along shallow Gulf Coast waterways, the wind can sometimes be every bit as important to a boating day as the printed tide table.

Why Tidal Datums Matter in Waterfront Real Estate

1. Dock and Boat-Lift Planning

A marine contractor may need accurate elevations and site conditions when evaluating piling height, lift placement, utilities and dock design. The needs of a bay boat can be very different from those of a larger center-console or sportfishing vessel.

2. Waterfront Depth and Usability

An attractive pier does not necessarily mean dependable boating access. I encourage buyers to evaluate usable depth at the lift, beside the dock and along the route to navigable water.

3. Surveys and Elevation Certificates

Surveys and elevation certificates should state the vertical datum used. When comparing older and newer documents, a licensed surveyor can determine whether the elevations are truly comparable or require conversion.

4. Coastal Construction

Finished-floor elevations, flood requirements, drainage, seawalls and site design involve different standards and authorities. A tidal benchmark can contribute to the technical framework, but current construction decisions should be made by the appropriate surveyor, engineer, contractor and permitting officials.

5. Shoreline and Permitting Questions

Mean high-water terminology may appear in environmental, shoreline and regulatory discussions. Buyers should not attempt to establish a legal boundary or permitting line from an online tide table or benchmark sheet. Site-specific professional and regulatory guidance is essential.

My Waterfront Due-Diligence Questions

The Question I Would Ask Before Making an Offer

Instead of asking only, “Does this property have a dock?” I would ask:

That one question opens the door to a much better waterfront evaluation. It brings together the dock, lift, depth, tide, channel, bridge clearance and real-world boating route. That is how I prefer to help buyers study waterfront property: not merely as a beautiful view, but as a complete coastal lifestyle.

Helpful Ono Island and Gulf Coast Resources

• Ono Island and Orange Beach Tide Outlook
• Ono Island No-Wake Zones and Boater Guide
• Boating from Ono Island to Perdido Pass
• Ono Island Canal Owners Association Guide
• Ono Island Waterfront Homes, Architecture and Boating Access
• Search Gulf Coast Waterfront Homes and Land by Waterway

Local Knowledge Meets Waterfront Due Diligence

Let’s Find the Waterfront Property That Truly Fits Your Boat

If you are considering an Ono Island home, homesite or boating property, I would be delighted to help you evaluate more than the view. Together, we can ask thoughtful questions about water depth, dock condition, boat-lift capacity, navigation routes, surveys and coastal due diligence.

EMAIL MEREDITH

Explore the Gulf Coast’s premier website for searching all real estate listings at SearchTheGulf.com.

This article is provided for general educational and real estate-planning purposes. Tidal datums, waterfront boundaries, flood elevations, navigable depth, dock permitting and construction requirements should be verified by appropriately licensed surveyors, engineers, marine contractors, environmental professionals, governmental agencies and legal counsel when applicable.