Cleanup, Disposal & Reuse

Prompt ash cleanup in urban areas is essential to minimise damage and disruption.

Ash Cleanup in Urban Areas

• Prompt clean-up of urban areas is essential to minimize damage and disruption.
• Ashfall accumulations of only a few mm (approx. 1/4 in) thick will generate large volumes of ash for collection and disposal.
• Experience has shown that efficient and effective cleanup operations need to be planned and coordinated in advance of ashfall events.
• If possible, delay clean-up until ash has stopped falling. However, repeated cleaning or multiple clean-ups may be necessary due to ash remobilization and to prevent ash from cementation.

Importance of Ash Characteristics

• In general, ash is highly abrasive and can cause accelerated wear and tear on equipment.
• Fine ash (<0.5 mm/<0.02 in particle size) readily remobilizes into the air, so that conventional street cleaning equipment may not pick it up.
• Coarse ash (>1 mm/<0.04 in particle size) is less readily remobilized, but may be crushed into smaller particles (e.g. by pedestrians, vehicles or during ash removal).
• Some ash deposits may 'cement' over time, especially if wetted and then dried.

Removing, transporting, and disposing of volcanic ash is a dirty, time-consuming, and costly challenge. Coordinated action by the public and by organizations can significantly lower costs and speed up the time it takes to remove most of the ash. The fall of a few millimeters of ash on an urban community will likely result in the need for collection and disposal of large quantities of material.

Proper disposal sites are needed quickly so that (1) ash does not have to be moved a second or third time; and (2) cleanup operations can begin immediately. To aid with this readiness, appropriate preplanning of disposal sites should be considered.

The time and effort required to remove and dispose of ash depends on the depth and aerial extent of the deposits, especially in urban and populated areas, and the availability of machinery (for example, from areas outside the zone of ashfall) to clean it up. Cleanup operations can take weeks to months to complete.

Several uncontrollable factors can impact the time required to remove ash and frustrate efforts of cleanup personnel:

• Additional ashfall before the cleanup operations are completed.
• Wind, which stirs and billows the ash into the air, can spread ash particles over areas already cleaned, subjecting the public and cleanup personnel to even more airborne ash and exposing machinery and equipment to increase wear or damage.
• Rain, which may help wash ash from roofs, but also lead to damaged gutters, short circuiting of power distribution systems, deposition of ash in low areas, and clogged storm-water drains and wastewater systems. Ash deposits may harden after being wet, making cleanup more difficult.

Ash cleanup operations can be time and resource intensive after a significant ashfall. Prompt requests for assistance and support from public and private sources located outside the zone can significantly help cleanup activities, especially if such requests are a part of existing regional contingency plans. Coordinating the use of local and regional resources helps to:

1. prioritize cleanup operations of specific facilities, infrastructure, and neighborhoods in concert with businesses and residents.
2. make certain that resources are used most effectively.
3. prevent cleanup activities from adversely affecting adjacent areas, infrastructure, or economic activities as much as possible.

In some cases, it may be helpful to restrict access to certain areas during clean-up operations. For example, after the 1980 eruption of Mt. St. Helens, a successful city-wide neighborhood clean-up program operated on a block by block basis using local and outside work crews and equipment in Eastern Washington. To minimize traffic problems, the city of Yakima restricted access to sixteen blocks in the Central Business District for several days.

If local fire-fighting equipment is used to help in cleanup activities, see recommendations to protect the fire-fighting capability and equipment.

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