CPESC Vegetative Stabilization 5

Question 1

Which type of erosion control blanket (ECB) is most appropriate for permanent installation in a channel with moderate flow velocities (2-5 ft/sec) where vegetation is expected to establish through the blanket?

Accepted Answer

Biodegradable coconut fiber (coir) blanket with open weave netting

Answer

Coir fiber blankets are durable enough for moderate channel flows, biodegrade slowly over 3-5 years, and allow vegetation to root through them for permanent stabilization.

Question 2

What is the primary advantage of using native plant species over non-native species in a permanent vegetative stabilization plan?

Accepted Answer

Native species are adapted to local climate and soils, require less maintenance, and support local ecosystems

Answer

Native species evolved under local conditions and therefore require less irrigation, fertilization, and long-term maintenance while also providing habitat value for native wildlife.

Question 3

A riparian buffer seeding is planned along a perennial stream bank. Which characteristic of the plant species selected is MOST critical for long-term bank stability?

Accepted Answer

Deep, fibrous root systems that bind soil particles

Answer

Deep fibrous root systems physically bind soil particles together and increase soil tensile strength, directly resisting the erosive forces of stream flow along the bank.

Question 4

What is 'dormant seeding' and when is it the preferred approach for vegetative stabilization?

Accepted Answer

Seeding in late fall after soil temperatures drop below germination thresholds so seed germinates the following spring

Answer

Dormant seeding places seed in soil after frost ends the growing season; seed overwinters and germinates naturally in spring, often producing excellent stands due to good seed-to-soil contact from freeze-thaw cycles.

Question 5

Which practice is used to establish vegetation on extremely steep rock cuts (greater than 1:1) where no soil exists for conventional seeding?

Accepted Answer

Hydraulic application of a soil-seed-fertilizer-mulch mixture bonded with synthetic tackifier or compost to rock surfaces

Answer

Hydro-mulching with a thick slurry containing compost, seed, fertilizer, and tackifier can adhere to bare rock faces and provide a growing medium sufficient for initial plant establishment.

(CPESC) Certified Professional in Erosion and Sediment Control Practice Test

(CPESC) Certified Professional in Erosion and Sediment Control Practice Test

CPESC Vegetative Stabilization 5