IA Water Auditing & Irrigation Efficiency

Question 1

The Irrigation Association defines a landscape irrigation audit as a process to evaluate:

Accepted Answer

How efficiently and uniformly an irrigation system applies water

Answer

An IA landscape irrigation audit evaluates system performance including uniformity, application rates, scheduling, and overall water use efficiency.

Question 2

Distribution Uniformity Low Quarter (DU_lq) is calculated by dividing the average of the lowest 25% of catch can readings by:

Accepted Answer

The overall average of all catch can readings

Answer

DU_lq = (average of lowest 25% catch readings) / (average of all catch readings) × 100%, indicating how uniformly water is distributed.

Question 3

What is the minimum acceptable DU_lq percentage recommended by the Irrigation Association for landscape systems?

Accepted Answer

70%

Answer

The IA recommends a minimum DU_lq of 70% for landscape sprinkler systems; values below this indicate significant waste or dry spots.

Question 4

During a catch can audit, how many cans are typically placed in a single irrigation zone?

Accepted Answer

At least 8–16 cans per zone in a grid pattern

Answer

IA protocols recommend placing a minimum of 8–16 catch cans in a grid pattern across the zone to capture variability and calculate meaningful DU.

Question 5

An irrigation audit station flow rate is determined by measuring:

Accepted Answer

The volume of water discharged from a zone over a measured time period

Answer

Station flow rate (GPM) is measured by recording the volume flowing through a meter or bucket test over a timed period while the zone runs.

IA - Irrigation Association Certification Practice Test