Dirt Project – DP-003

San Bernard River Corridor (Cat Spring, TX)

Project: Dirt Project

Entry ID: DP-003

Location: Cat Spring, Texas (San Bernard River Corridor)

Associated Expedition: EXP-003

Terrain Type: Gulf Coastal Plain – Sandy Depositional System

Geologic Context: Early Pleistocene (Willis-type deposits) → Modern Alluvial System

Date Collected: March 14 and 15 2006

Samples: DP-10 → DP-16

Overview

The Cat Spring course sits within the Gulf Coastal Plain, a landscape built over long periods of time by rivers moving toward the Gulf of Mexico. Those rivers carried enormous volumes of sand, silt, and gravel, spreading them across wide, low-lying areas and gradually building up thick layers of sediment. What looks like simple ground at the surface is actually the top of a much deeper system—stacked deposits laid down by earlier river systems and preserved over time.

From a distance, this landscape appears flat. The horizon is broad, elevation changes are subtle, and nothing immediately suggests complexity. But that impression breaks down as soon as you move across it on foot. At ground level, the terrain is loose, uneven, and constantly shifting underfoot. Sandy surfaces give way in places, firm up in others, and are interrupted by shallow cuts, small ridges, and irregular slopes. These features are not random. They are the result of modern processes actively working on top of older deposits.

Water is the primary driver. Rainfall and runoff move easily through sandy material, carving small channels and weakening slopes. The San Bernard River continues to rework sediment along its course, while smaller creeks and drainage paths cut into the surrounding terrain. At the same time, some areas remain stable long enough for finer material and organic matter to accumulate, beginning the transition from loose sediment into soil.

What you experience on the course is the interaction of all of these processes at once:

• older sandy deposits forming the base

• active river sediment near the channel

• runoff carving and reshaping the surface

• localized stability where soil begins to develop

This is why the terrain can look flat on a map but feel broken and inconsistent underfoot. The large-scale structure is simple, but the surface is constantly being modified.

This entry documents that system directly through six sediment samples collected across the San Bernard River corridor and the race course, capturing different stages of that process in place.

Field Observations – Terrain

Despite its classification as coastal plain, the course terrain showed:

• repeated short climbs and descents

• uneven sandy footing

• shallow drainage cuts

• alternating loose and compact ground

These features reflect erosional dissection, where water runoff cuts through sandy material and creates a broken surface. The terrain is not built by elevation. It is built by water movement across soft ground.

Sample Set Overview

The samples form a continuous gradient across the landscape:

River → Bank → Stable Surface → Course → Creek → Soil

This sequence captures the transition from active sediment transport to long-term stabilization.

DP-10 – Dry Sand Taken From San Bernard River Bank

GPS Coordinates (FM 949 bridge crossing)

Latitude: 29.8036° NLongitude: -96.3310° W

• Light-colored quartz grains

• Loose, non-cohesive

• Sub-angular grain shapes

Interpretation:Recently exposed alluvial sand deposited by the San Bernard River.

DP-11 – Wet San Bernard River Mud (Active Channel)

GPS Coordinates (FM 949 bridge crossing)

Latitude: 29.8036° NLongitude: -96.3310° W

• Fine-grained matrix (sand + silt + mud)

• Cohesive when wet

• Iron staining / darker coloration

  
  

Interpretation:Active alluvium — sediment currently being transported by the river, including fines.

DP-12 – Stabilized Surface (~100 Yards from River)

GPS Coordinates (FM 949 bridge crossing)

Latitude: 29.8036° NLongitude: -96.3310° W

• Mixed grain sizes

• Surface coatings

• Early structure development

Interpretation:Transition zone from sediment to developing soil, with reduced reworking.

DP-13 – Race Course Surface

Collection Context: Taken just off the race course near Mile 3 (Super distance) at 7iL Ranch, Cat Spring, Texas.

GPS Coordinates Latitude: 29.90045° N Longitude: -96.30728° W

• Sandy with mixed fines

• Irregular structure

• Uneven compaction

Interpretation:Represents older sandy deposits forming the base of the course, modified by erosion and runoff.

DP-14 – Creek Crossing Sediment (Mud)

Collection Context: Taken directly from the creek bed at a course crossing near Mile 4 (Super distance) on the 7iL Ranch race course, Cat Spring, Texas.

GPS Coordinates: Latitude: 29.8036° N, Longitude: -96.3310° W

• Mixed grain types (quartz + darker minerals)

• Variable grain size

• Locally reworked

Interpretation:Sediment from a small drainage system, actively reshaping the terrain.

DP-16 – Soil / Organic Layer

Collection Context: Taken from a vegetated area just off the race course Mile 5 of Super Course at 7iL Ranch, Cat Spring, Texas, in a zone showing stable ground cover and minimal disturbance.

GPS Coordinates: Latitude: 29.90045° N, Longitude: -96.30728° W

• Fine grains

• Organic fragments

• Darker coloration

  
  

Interpretation:Stabilized soil layer, indicating long-term surface development.

System Interpretation

The Cat Spring landscape is composed of interacting processes:

Zone	Process	Surface Expression
River	Active transport	Wet sediment, mud
River margin	Deposition	Loose sand
Adjacent land	Stabilization	Firmer surface
Ranch surface	Older deposits	Uneven footing
Creek systems	Erosion	Cuts, slopes, channels
Soil zones	Biological activity	Dark, stable ground

Deep Time Linkage

Then → Now → Surface

Then (Early Ice Age – ~1–2 million years ago)

Large river systems deposited thick layers of sand across southeast Texas.These deposits form the structural base of the region.

→ Broad, sandy floodplains→ Massive sediment accumulation→ Formation of units like the Willis-type deposits

Now (Modern System)

The San Bernard River continues to:

• cut into older deposits

• transport and redistribute sediment

• feed smaller drainage systems

At the same time

• rainfall drives surface erosion

• creeks carve into the terrain

• sediments are constantly reworked

Surface (What We Ran On)

The race course represents a composite surface:

• ancient sandy deposits (foundation)

• modern river sediment (active zones)

• erosion features (terrain variation)

• soil development (stability zones)

The ground is not one thing.It is time layered into a surface.

Expedition Summary

This is not just sand.

This is a multi-stage sediment system where:

• ancient deposits provide the base

• rivers rework material

• runoff reshapes the surface

• biology stabilizes portions over time

You are not running on terrain.

You are running across different stages of landscape evolution at once. The Cat Spring course looks flat on a map, but the ground tells a different story. Near the San Bernard River, sediment is loose and actively reworked. Farther away, the surface becomes more stable and soil-like. Across the course, small creeks and runoff have carved through older sandy deposits, creating constant variation in footing and elevation. What appears uniform at scale becomes a broken, shifting surface underfoot.