Location: In the past decade, the capital of Texas has grown steadily. Populated about 800,000 people large, the city of Austin is ranked as the fourth largest city in the state and the fourteenth largest across the country. However, it was once a small town called Waterloo where Shoal Creek was the western most boundary of the city. Shoal Creek, named by Edwin Waller, is an urban stream that flows through North Austin’s Allendale residential area, down Pease District Park, West Downtown Austin, past the Austin Public Library, and empties out into Lady Bird Lake.
Watershed details: To begin with, a watershed is an area of land in which all water within said area drains in the same place, and Shoal Creek’s watershed is the largest in the city of Austin, with a drainage area as of 2016 of almost 13 square miles long and growing year by year.
Water quality issue: Shoal Creek has many interconnected issues, the first being water quality. In a natural watershed, water is typically absorbed into the soil and into aquifers that lead to groundwater reservoirs called groundwater inflow. When water overflows and has trouble seeping into the ground due to heavy rain, runoff brings the water to collect into the main drainage system of the watershed. This, however, is a little different for urban watersheds like Shoal Creek. With Shoal Creek’s 13 sq mile drainage area, as of 2016 53% of the watershed’s surface is covered by impervious cover, like asphalt and concrete from urban development. As it implies, these impervious surfaces stop water from naturally seeping into the ground, and in an urban setting like Austin, this means that anything lying around, like littered trash, the fecal matter of a dog that its owner didn’t pick up, pollution from construction sites, raised sediment, and residents’ garden fertilizer, is rushed into Shoal creek when it rains through urban runoff, contributing to the creek’s poor water quality.
Soil erosion: Soil erosion is another important issue Shoal Creek faces. Erosion is the removal and transport of soil by wind, water or other natural means. We typically see all three forms of erosion take place across the watershed: surface erosion, gully erosion, and soil mass movement. At its most basic level erosion is generated by the force of consistent raindrops and the watershed is a well defined channel, high water levels increase the capacity to transport sediments downstream and we’re able to see gully erosion develop over time. Landslides are the most severe and catastrophic form of erosion. Because the watershed is located in a highly developed area, water flows quickly over the landscape, and in addition to carrying contaminated sediments, causes significant erosion and destabilization of the creek’s bank. In May 2018 and 2019, at the peak of Austin’s Flood season, major landslides occurred. Both caused significant destruction of public and private land, thankfully no one was hurt.
Flooding: Another challenge within the Shoal Creek watershed is its geographic location. The watershed itself is a part of Texas’ Flash Flood Alley, an area where the convergence of cold fronts and warm Gulf Air mass along with hilly terrain and thin topsoil cause flash floods. Additionally, the watershed is classified as a 100-year floodplain, meaning one year within the total 100 years has a chance of having a massive flood, or a one percent chance every year. Because of this the area is historically prone to flooding, there are
Rethink water with SCC: The numerous issues with storm drains has made a certain group to rethink water as a whole. When addressing flood mitigation, there are two plausible ways in which we can think about water. One way involves looking at the waterway itself, or just Shoal Creek. Methods for addressing this viewpoint usually involves storm drains, where water is seen as an excessive byproduct or something we want to move out of the creek as quickly as possible. The other way of addressing floodwaters is by managing water as a valuable resource, something that is worth keeping. The Shoal Creek Conservancy, or SCC for short, is a nonprofit organization founded in 2013 that targets the many issues plaguing the creek: flooding, poor water quality, soil erosion, native habitat loss, and groundwater inflow. The group’s methodology of addressing these concerns does not include examining the creek alone, but the whole Shoal Creek watershed.
Mitigation: To address the issues surrounding the watershed, the SCC alongside the City of Austin has conducted home buyouts in which land is negotiated and purchased from willing residents to expand the flood bank of the creek, channel improvements, bank stabilization, and storm drain improvements. Rather than using taxpayer dollars to just create flood infrastructures that function only as flood mitigation, the group has also aided the City of Austin in rethinking flood infrastructure from a waste of residents’ taxes to amenities that can be beneficial in flood mitigation as well as usable by the public. One idea was to create recreational detention basins, like floodable parks or sports fields, in which water could be temporarily stored during devastating floods to mitigate damage. An example is Houston’s Willow Waterhole Greenway, a floodable park intended to store water within a series of ponds. In Conjunction with the Parks and Recreation and Watershed Protection department another method in addressing the watershed’s flooding issues came in the form of riparian zone restoration. Riparian zones are areas of land by the bank that act as a buffer during heavy rain to stunt and reduce the amount of water rushing into the creek as well as increasing groundwater inflow. This is done by planting and cultivating native plant life at degraded sites in which vegetation cover has been reduced by mowing or development. The Watershed Protection Department has also focused on removing parts of Shoal Creeks storm drain pipes and replacing then with swales, shallow depressions in the ground that slow down runoff into the creek, allow for increased groundwater inflow, while also supporting native plant and insect life that can be valuable to park goers. All of these flood mitigation initiatives have provided a value other than flood mitigation back to the community funding the projects.
What’s next? As of december 2020 there are coordinated plans between the City of Austin and Shoal Creek Conservancy underway to gather reports, maps and other data to gain an understanding of what has been completed and what needs to be done in order to manage the Shoal Creek Watershed. SCC is pushing for flood mitigation projects and programs to minimize the intensity of flooding in the area. As of now, the only projects being funded and executive are those that are helping the physical appearance of Shoal Creek.
Helpful Reference Links:
SHOAL CREEK WATERSHED PROTECTION PLANNING SCOPING & FUNDING STRATEGIES
The History of Shoal Creek
Watershed Urbanism: Shoal Creek's Infrastructural Future
Shoal Creek Flooding-Staying Aware and Staying Safe
What's the rush? Slowing stormwater down…from pipes to swales to creeks
Riparian Zone Restoration: Shoal Creek Greenbelt
Unsafe bacteria at creeks, streams and swimming holes
WATER CHEMISTRY OF SHOAL CREEK AND WALLER CREEK, AUSTIN, TEXAS, AND POTENTIAL SOURCES OF NITRATE
Allandale Neighbor
Shoal Creek Summary Aug 2014
Lower Shoal Creek Flood Hazard Mitigation Study
Flooding in the Shoal Creek Watershed
Watershed details: To begin with, a watershed is an area of land in which all water within said area drains in the same place, and Shoal Creek’s watershed is the largest in the city of Austin, with a drainage area as of 2016 of almost 13 square miles long and growing year by year.
Water quality issue: Shoal Creek has many interconnected issues, the first being water quality. In a natural watershed, water is typically absorbed into the soil and into aquifers that lead to groundwater reservoirs called groundwater inflow. When water overflows and has trouble seeping into the ground due to heavy rain, runoff brings the water to collect into the main drainage system of the watershed. This, however, is a little different for urban watersheds like Shoal Creek. With Shoal Creek’s 13 sq mile drainage area, as of 2016 53% of the watershed’s surface is covered by impervious cover, like asphalt and concrete from urban development. As it implies, these impervious surfaces stop water from naturally seeping into the ground, and in an urban setting like Austin, this means that anything lying around, like littered trash, the fecal matter of a dog that its owner didn’t pick up, pollution from construction sites, raised sediment, and residents’ garden fertilizer, is rushed into Shoal creek when it rains through urban runoff, contributing to the creek’s poor water quality.
Soil erosion: Soil erosion is another important issue Shoal Creek faces. Erosion is the removal and transport of soil by wind, water or other natural means. We typically see all three forms of erosion take place across the watershed: surface erosion, gully erosion, and soil mass movement. At its most basic level erosion is generated by the force of consistent raindrops and the watershed is a well defined channel, high water levels increase the capacity to transport sediments downstream and we’re able to see gully erosion develop over time. Landslides are the most severe and catastrophic form of erosion. Because the watershed is located in a highly developed area, water flows quickly over the landscape, and in addition to carrying contaminated sediments, causes significant erosion and destabilization of the creek’s bank. In May 2018 and 2019, at the peak of Austin’s Flood season, major landslides occurred. Both caused significant destruction of public and private land, thankfully no one was hurt.
Flooding: Another challenge within the Shoal Creek watershed is its geographic location. The watershed itself is a part of Texas’ Flash Flood Alley, an area where the convergence of cold fronts and warm Gulf Air mass along with hilly terrain and thin topsoil cause flash floods. Additionally, the watershed is classified as a 100-year floodplain, meaning one year within the total 100 years has a chance of having a massive flood, or a one percent chance every year. Because of this the area is historically prone to flooding, there are
- two dates in particular that we’re going to focus on: May 27, 1981 and May 25, 2015, in which the floods were eerily similar. The floods that happened on these two dates were significant floods and coincidentally fell on the same holiday, Memorial Day. The original 1981 memorial flood saw such significant flooding that in 1982 the residents and city of Austin worked together to plan and construct more efficient flood infrastructure. However, the main method used in addressing flooding within the watershed contributed to the other two issues we discussed earlier: poor water quality and soil erosion.
Rethink water with SCC: The numerous issues with storm drains has made a certain group to rethink water as a whole. When addressing flood mitigation, there are two plausible ways in which we can think about water. One way involves looking at the waterway itself, or just Shoal Creek. Methods for addressing this viewpoint usually involves storm drains, where water is seen as an excessive byproduct or something we want to move out of the creek as quickly as possible. The other way of addressing floodwaters is by managing water as a valuable resource, something that is worth keeping. The Shoal Creek Conservancy, or SCC for short, is a nonprofit organization founded in 2013 that targets the many issues plaguing the creek: flooding, poor water quality, soil erosion, native habitat loss, and groundwater inflow. The group’s methodology of addressing these concerns does not include examining the creek alone, but the whole Shoal Creek watershed.
Mitigation: To address the issues surrounding the watershed, the SCC alongside the City of Austin has conducted home buyouts in which land is negotiated and purchased from willing residents to expand the flood bank of the creek, channel improvements, bank stabilization, and storm drain improvements. Rather than using taxpayer dollars to just create flood infrastructures that function only as flood mitigation, the group has also aided the City of Austin in rethinking flood infrastructure from a waste of residents’ taxes to amenities that can be beneficial in flood mitigation as well as usable by the public. One idea was to create recreational detention basins, like floodable parks or sports fields, in which water could be temporarily stored during devastating floods to mitigate damage. An example is Houston’s Willow Waterhole Greenway, a floodable park intended to store water within a series of ponds. In Conjunction with the Parks and Recreation and Watershed Protection department another method in addressing the watershed’s flooding issues came in the form of riparian zone restoration. Riparian zones are areas of land by the bank that act as a buffer during heavy rain to stunt and reduce the amount of water rushing into the creek as well as increasing groundwater inflow. This is done by planting and cultivating native plant life at degraded sites in which vegetation cover has been reduced by mowing or development. The Watershed Protection Department has also focused on removing parts of Shoal Creeks storm drain pipes and replacing then with swales, shallow depressions in the ground that slow down runoff into the creek, allow for increased groundwater inflow, while also supporting native plant and insect life that can be valuable to park goers. All of these flood mitigation initiatives have provided a value other than flood mitigation back to the community funding the projects.
What’s next? As of december 2020 there are coordinated plans between the City of Austin and Shoal Creek Conservancy underway to gather reports, maps and other data to gain an understanding of what has been completed and what needs to be done in order to manage the Shoal Creek Watershed. SCC is pushing for flood mitigation projects and programs to minimize the intensity of flooding in the area. As of now, the only projects being funded and executive are those that are helping the physical appearance of Shoal Creek.
Helpful Reference Links:
SHOAL CREEK WATERSHED PROTECTION PLANNING SCOPING & FUNDING STRATEGIES
The History of Shoal Creek
Watershed Urbanism: Shoal Creek's Infrastructural Future
Shoal Creek Flooding-Staying Aware and Staying Safe
What's the rush? Slowing stormwater down…from pipes to swales to creeks
Riparian Zone Restoration: Shoal Creek Greenbelt
Unsafe bacteria at creeks, streams and swimming holes
WATER CHEMISTRY OF SHOAL CREEK AND WALLER CREEK, AUSTIN, TEXAS, AND POTENTIAL SOURCES OF NITRATE
Allandale Neighbor
Shoal Creek Summary Aug 2014
Lower Shoal Creek Flood Hazard Mitigation Study
Flooding in the Shoal Creek Watershed
