Your pond is leaking. Here's the fix.
Engineered clay is the most reliable, cost-effective liner for agricultural and stormwater ponds — and most people don't know how to use it correctly.
Why ponds lose water:
01 Sandy or gravelly subsoil - High permeability lets water drain straight through the base and sides of your pond.
02 Shrink-swell cracking - Expansive soils crack when they dry out during drought, opening fast preferential flow paths.
03 No engineered liner - Pond was built assuming native soil would self-seal over time — in most DFW soils, it doesn't.
The key characterstics of Pond Clay:
CLASSIFICATION - CL — Low-plasticity clay (USCS)
KEY PROPERTY - Hydraulic conductivity < 1x10-7 cm/sec
HOW IT WORKS - Fine particles fill pore spaces, creating an impermeable barrier
BEST USE - Pond liners, stormwater basins, agricultural reservoirs
Here are the stages to go through:
Test your native soil
✓ Why it matters: Not every pond needs a full clay liner. Testing first tells you whether your native sub soil will seal — or how much clay you actually need to import.
✓ What to test: Grain size distribution (ASTM D422) , Plasticity Index (ASTM D4318) , Hydraulic conductivity (ASTM D5856) , Target: Hydraulic conductivity ≤ 1×10⁻⁷ cm/sec
Source the Right Clay
Not all clay is equal. You need material that meets engineering specs — not just anything with a
clay-like feel.
✓ Fines content: > 50% passing #200 sieve
✓ Plasticity Index: PI 10–30 (workable, not expansive)
✓ Classification: CL or CL-ML under USCS
✓ Avoid: CH clays — they shrink-swell and crack
Hudson Aggregates supplies tested CL clay in the DFW area. Ask for the lab report — we provide it with every order.
Prepare the Subgrade
✓ Clear vegetation - Remove all organic material from the pond floor and slopes. Roots create preferential flow paths.
✓ Scarify the base - Till subgrade 6" deep to create a bond between native soil and the incoming clay liner.
✓ Moisten subgrade - Bring native soil to near-optimum moisture before placing clay — dry soil repels water initially.
✓ Shape slopes - Maximum 3H:1V side slopes for stable clay liner placement and effective compaction.
Place & Compact in Lifts
This is where most DIY pond liners fail. Clay must be placed in controlled lifts and properly
compacted — not just dumped in.
✓ Lift Thickness - Place in 6–8" loose lifts (compacts to ~6")
✓ Total Thickness - Minimum 12" compacted (18–24" preferred)
✓ Moisture Control - Compact at optimum moisture content ±2%
✓ Equipment - Sheepsfoot or padfoot roller for best bond between lifts
✓ Coverage - Extend liner 3 ft beyond full pool elevation on all slopes
Test & Protect the Liner
Before you fill permanently, verify the liner is working — and protect it from future damage.
✓ Flood test - Fill slowly and monitor seepage rate over 72 hours before accepting the liner.
✓ Add cover soil - Place 12" of topsoil over liner on slopes to prevent desiccation cracking in summer.
✓ Establish vegetation - Grass cover holds the liner in place and reduces wave erosion on slopes.
✓ Limit traffic - Keep heavy equipment off liner edges once the pond is filled.
