The first step in the Willow Waterhole Prairie Management Plan was to map the full extent of the coastal prairie remnants and the Texas prairie dawn colonies, which were found in two locations in the Willow Waterhole Prairie Management Area (marked North Sector and South Sector on the site map below). The Flood Control District then launched a three-phased effort to protect this species by conserving and restoring its coastal prairie ecosystem.
Phase 1: in 2010, involved the partial removal of trees and undesirable vegetation in the North Sector (refer to site map), which is located south of the Willowbrook and Post Oak Manor neighborhoods. Next, the Flood Control District started inventorying and monitoring the ecosystem, which has shown a remarkable ability to return to its original, natural state as a coastal prairie. To date, over 300 species of native plants have been found within this area, including many colorful wildflowers.
Phase 2: in November 2013, and included the partial removal of trees and undesirable vegetation in the South Sector, which is located near the eastern end of Gasmer Drive, north of South Main Street; and the partial removal of trees and undesirable vegetation in the North Sector. A forested buffer (shown in light green on the site map) will remain between the neighborhoods and the North Sector. District experts and community leaders agreed upon allowing individual trees to remain within the prairie as mottes: groups of trees interspersed within a prairie. Refer to the site map for location of current mottes in the North Sector.
Phase 3: in late 2015, and included removal of trees, undesirable vegetation, and debris within the South Sector. Final motte locations can be seen in the site map below. A forested buffer (shown in light green on the site map) will remain between the prairie area and railroad tracks.
The following procedures were
followed during each Phase of prairie restoration:
- Tree Removal: While the effort will require the removal of some
larger trees, the Flood Control District plans to avoid where
possible the removal of healthy, desirable large trees in the two sectors.
Tree removal is a necessary step to establishing a coastal prairie habitat
because fast-growing trees can overwhelm and displace the grasses and
wildflowers that give prairies their valuable characteristics.
The Harris County Flood Control District’s contractor will
remove shrubs, saplings, and small trees in the North and South sectors.
Hardwood trees larger than approximately 10 inches in diameter cannot be
removed due to equipment limitations. Trees larger than 10 inches
in diameter will be evaluated for removal or to remain as a motte.
Tree Evaluation: Flood Control District biologists will
evaluate the condition, location, number, and species of the
remaining trees within the Prairie Management Area to determine which
trees to include as mottes, which are groupings of trees. These selected
trees will be flagged, cataloged, and mapped.
- Motte Creation:
Based on the site-wide tree evaluation, the Flood
Control District’s contractor will remove trees that were not
selected to be included within the mottes.
- Prairie Establishment: Mulch created from tree removal will be
raked into the motte areas. This will reveal the buried prairie seedbank
and soil, allowing the native grasses and wildflowers to germinate and
- Undesirable Vegetation Removal: The Flood
Control District’s contractor will remove all exotic, or non-native,
vegetation in the North and South sectors, including Chinese Tallow, Crepe
Myrtle, Pampas grass, Oleander, and others. This is done to
prevent encroachment by species with the ability to displace the
Texas Prairie Dawn and other native species.
- Management, Monitoring, and
Maintenance: The Flood Control District will manage the Willow
Waterhole Prairie Management Area according to the Willow Waterhole
Prairie Management Plan. Management activities include cyclic or
semi-annual high-deck mowing, woody plant removal, and select herbicide
application. The Flood Control District will adjust the management
plan as needed.
As this site becomes established, it will be a great community
asset by conserving one of the last urban coastal prairie sites in Harris
County, and will offer educational opportunities for children and adults to
learn about these endangered coastal prairie habitats.