College Lake 2

The torrential downpour of Aug. 2 put the dam at College Lake in extreme danger. Lakeside Drive, which is atop the dam, was closed for several weeks as officials assessed any damage.

Since the flood event on Aug. 2 and subsequent draining of College Lake, Lynchburg City and the University of Lynchburg have been working together to develop and realize a shared vision for the future of College Lake. In August, we announced plans to leave the lake dewatered, eventually replace the dam with a bridge and convert the lakebed into a wetlands laboratory with educational and recreational benefits. We continue to pursue that vision.

However, we also continue responding to an ever-changing situation that requires adaptation. We want to take the opportunity to bring the Lynchburg community into the conversation and explain what we have done and what we will do in the coming months, to protect public safety and the environment in the College Lake watershed.

In the weeks following the flood, we have engaged experts on dam safety and environmental issues and worked closely with various regulatory agencies in order to make the best decisions possible for public safety, environmental protection and restoration — all while keeping in mind the best use of limited financial and human resources.

This dialogue has led to a decision to temporarily refill College Lake until the dam is removed. On Oct. 19, the city closed the sluice gate that allowed the lake to drain. Given our previous announcements, this change of strategy may surprise many in the community. This decision was not made lightly nor without intense research and debate by both the professionals employed by our organizations and by our external colleagues. Through analyzing current data and assessing all relevant factors, we know that this is the best path forward to protect public safety, conserve public funds, mitigate negative environmental impacts and allow us to prepare for the removal of the dam and restoration of the lakebed.

The original decision to drain the lake was made after College Lake dam suffered structural damage in August and under advice from Black & Veatch, an internationally recognized dam safety and engineering firm. We believed that lowering the water level would allow us to begin restoration efforts and also create a stormwater basin, making it less likely that a storm would overtop the road. After discussing this plan at length with the State Department of Conservation and Recreation Division of Dam Safety and numerous other regulatory officials, consultants, city staff and university staff, it was agreed that we should keep the lake dewatered indefinitely.

After the lake was dewatered, however, the lakebed changed in several unexpected ways. Sediment control has been a more concerning issue than originally anticipated. Blackwater Creek flows into the lakebed and out toward the James River through the dam’s outfall. We found that the loose sediment that had accumulated on the lakebed over the past eighty years was shifting downstream and building up around the dam’s intake at a rate faster than anticipated, possibly due to above-average rainfall. It was flowing downstream through Blackwater Creek to the James River and negatively impacting our downstream watershed.

In order to better understand this situation and move forward with stabilizing the stream bed, the city engaged Art Perola of the University of Louisville, one of the nation’s foremost stream and wetland restoration experts, to analyze the College Lake ecosystem. He explained how the rapid erosion is caused by Blackwater Creek attempting to even out its streambed elevation. This means that all of our attempts to regulate sediment flow before the dam removal will simply be negated by the stream attempting to correct its own slope. Refilling the lake will slow the flow of sediment downstream and allow the city and the University to work together on long-term plans for sediment control and lakebed restoration.

Another concern was the constant flow of debris into the lakebed from upstream areas. With the low-level outlet open and the lake dewatered, the city needs to keep the outfall clear of any debris clogs. Shortly after repairs were made to the dam, the city installed a large pipe around the intake and welded a trash grate to its top to keep debris from clogging the outfall. However, since dewatering the lake and installing this trash grate, the city has needed to close Lakeside Drive multiple times in order to facilitate debris removal with a large crane — at a cost of at least $10,000 each time. Additionally, during the rain event associated with Hurricane Florence, a large amount of debris flowing downstream broke the trash grate, rendering it ineffective. It became clear that performing this maintenance after every large storm is simply unsustainable in terms of cost and the burden it places on the 17,000 people who travel on Lakeside Drive each day. With the lake refilled, this maintenance and its road closures will no longer be necessary and the city will be able to control the dam at all times.

This, of course, raises the question: Why is it safe to refill College Lake? In the weeks following the Aug. 2 storm, Black & Veatch developed extensive modeling scenarios to determine how much rain it would take to fill the lake, overtop the dam and create a potential breach scenario (which would result in an evacuation of the downstream area). The data clearly shows that the risk of the dam overtopping is only minimally reduced with the lake dewatered. Even in its dewatered state, the lake can refill to normal pond with as little as one inch of rain. While it is possible that future overtopping — and a subsequent downstream evacuation like we experienced in August — could occur, we now know that there is not a significant reduction in risk with the lake dewatered. This means that the costs and risks of keeping the lake dewatered greatly outweigh any potential benefits that we originally believed the lake being dewatered might offer. The marginal reduction in risk can be further achieved with the installation of “real time” monitoring equipment and an enhanced emergency action plan.

We recognize that this is a significant departure from our previous course of action. Given the information available at the time, it was the right decision to dewater the lake. However, new data has revealed a better course of action for public safety and resource allocation.

The scenario at College Lake is complex, and there are no simple answers. Since Aug. 2, both the city and the university have been operating in an emergency response situation — each new rain event creates unexpected challenges that require an immense amount of time, energy and resources. We believe that by refilling the lake, we will be able to redirect our efforts away from emergency response and towards the long-term planning needed to design a bridge, remove a dam and create a world-class wetland learning laboratory.

This project is, in many ways, a laboratory for all of us — we do not know of any other communities addressing failing dams from the perspective of a public-private partnership. As we look to the future, we will do so with an eye to public safety first and foremost. The city’s Emergency Action Plan will be further enhanced by adding real-time monitoring and instrumentation, and the city will continue to personally monitor the dam and lake at hourly intervals during flood watches and warnings, something that will enable us to proactively and quickly respond to any changes. Additionally, both the university and the city are working cohesively to develop consistent analytical methods to continue the water quality sampling of Blackwater Creek and the lake for bacteria and sediment to monitor the health of the ecosystem.

We know that College Lake is near and dear to many in Lynchburg. Many people have grown up swimming in or skating on the lake; many enjoyed jogging or walking along its banks. We are committed to working together to determine the best path forward towards restoring an ecologically and recreationally rich area. Even though refilling the lake may seem like a step backward, it is actually a step forward. It allows us to use our resources to ensure the safety of those downstream and to thoughtfully design the lakebed’s restoration. Welcome to our laboratory — we look forward to continuing the conversation with you in the coming years.

Svrcek is the city manager of Lynchburg; Garren is president of the University of Lynchburg; Wodicka is deputy city manager of Lynchburg; Mitchell is director of Lynchburg Water Resources; and Henry-Stone is an associated professor of environmental studies at the University of Lynchburg. They wrote this column for The News & Advance.

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