VICKSBURG, Miss. - The expertise of U.S. Army Engineer Research and Development Center (ERDC) team members was called upon recently in the aftermath of two deadly landslides in Afghanistan.
“After the mudslides, officials say the site became a mass grave for the nearby village of Abi Barack,” said Coastal and Hydraulics Laboratory (CHL) Research Hydraulic Engineer Dr. Mark Jourdan, who led the ERDC team. “After the landslide struck, residents from a nearby village rushed to the scene to help dig people out and the second landslide struck, killing many of the rescuers. The mudslide was also blocking the flow of the river.”
According to General Engineer Vernon Lowry, a request for a hydraulic assessment came from the International Security Assistance Force (ISAF) via the USACE Reachback Operations Center (UROC).
“The UROC provides rapid, reliable and relevant solutions to Warfighters and Civilians across the full operational and natural disaster spectrum. It allows deployed personnel access to subject matter experts (SMEs) to help achieve a detailed analysis to their problems,” Lowry said.
A team of ERDC experts was formed to meet the request. The team was comprised of CHL members Jourdan, Darla McVan, Clay LaHatte, Gary Brown, and Jeffrey Ellis; and Geotechnical and Structures Laboratory (GSL) team members Dr. Oliver-Denzil Taylor, Chad Gartrell, Rhonda Taylor, Jerry Rushing, Craig Hancock and Amanda Huskey.
The multi-experienced team was tasked to provide the hydraulic assessment of the dam in the Argo District, Badakhshan Province, Afghanistan. The rushed timeline posed no challenge to the team.
“We were given five days and finished in four,” Jourdan said.
To find a solution, the various team members were tasked with providing findings in their specific areas of expertise. The first step was an accurate and current understanding of the situation. According to Rushing, current satellite imagery of the area was downloaded to aid in the situation assessment.
With the common picture, the team set out to complete the task using a combination of models.
“The first was the Decision Support System – Water Infrastructure Security ( DSS-Wise) model,” said Jourdan. “The DSS-Wise is a dam breach model developed at the University of Mississippi.”
The computer model simulates the flooding, estimates the total drawdown of flood waters, and predicts how long it will take the waters to recede. The model incorporates and integrates thousands of data points from geographical and satellite information and paints a current picture and prediction to help Afghanistan’s disaster efforts.
“The flooding scenarios were set up with a geographic information system (GIS) –based, user-friendly processor that provided a two-dimensional, accurate predictive map of flood arrival times, depths and velocities for the specified scenario,” Jourdan said.
The second model used was the Hydraulic Modeling System (HEC-HMS)
“This model is designed to simulate the precipitation-runoff processes of dendritic drainage basins,” said Jourdan. “It is designed to be applicable in a wide range of geographic areas, which includes large river basin water supply and flood hydrology, and small urban or natural watershed runoff.”
The third model used was the ERDC-developed AdH/SedLib model.
“The AdH has many features which make it unique and applicable for a wide variety of applications,” Jourdan said.
The model allows calculation of transport of both cohesionless sediment (sand) and cohesive sediment (clay and silt). When linked to SedLib, it computes suspended sediment transport as well as associated changes while coupled to the hydrodynamic computations.
Using the combination of models, the team provided a hydrologic model of the flow behind the artificial dam that determined how long until the dam would be overtopped. The dam breach model illustrated areas prone to flooding downstream and the sediment model revealed how the mudslide could erode once a channel was cut through it.
In a fast-paced environment such as this, providing concise information was essential. UROC emergency operations specialists were the link between ISAF and ERDC SMEs.
“Once the SMEs composed their responses, we compiled the information and distributed it to the requestor’s country,” Huskey said.
“It was a team effort,” Jourdan said. “Each member of the team provided expertise for the solution. We submitted our assessment and engineering recommendations to assist in proper construction of the permanent solution,” he said.
The findings included:
- There was minimal chance of significant flood damage
- It was very unlikely that a “catastrophic” breach could form at the site
- Siphons should be installed to divert the water over the mud slide
- A long time solution is needed to establish a permanent channel
“This type of response action is one of the most important missions we carry out in the area of civil engineering,” said Gartrell. “We provide so many things for both the nation and the Warfighter, but it definitely makes you realize what a small world we live in when we have an opportunity to help other people, who will likely never know or meet us, on the other side of the world, from right here in Vicksburg.”
“The mudslide was devastating to the Afghanistan people – affecting hundreds of homes and people. We were glad to be able to provide our expertise to help and hopefully divert any future similar event,” Jourdan said.
Because of their expertise and quick response, the ERDC team once again provided innovative solutions for a safer, better world for the Afghan people.