The Last Walk<br />A Low Impact Development created for Independence Parkway<br />Team 07183<br />
Implementation of a Low Impact Development Design<br /><ul><li> Provide a model roadway corridor that could be implemented throughout the State.
Provide the equivalent of a zero percent impervious roadway system (“No Impact Development”)
Reduce surface runoff pollutants and total suspended solids from first flush rain events.
Greatly reduce maintenance needs of the pavement and landscape through durable engineering design and low impact landscape.
Provide a platform for public art and education in a highly visible location</li></ul>Project Goals<br />
Location<br />Project located along Independence Parkway in East Harris County between I-10 and S.H. 225.<br />
Site History<br /><ul><li> On April 20, 1836, the Texas Army, led by General Sam Houston, established camp at Lynch’s ferry.
April 21, 1836, General Sam Houston engaged in battle against Mexican forces led by President Antonio López de Santa Anna.
In eighteen minutes, the Texas Army defeated the Mexican forces to win Texas’ independence from Mexico</li></li></ul><li>Existing Conditions<br />Independence Parkway – Looking North<br />Independence Parkway – Looking South<br />
WPM<br />Roadway Layout<br />BEGIN LID PROJECT<br />MATCH LINE A<br />INDEPENDENCE PARKWAY (120’ ROW)<br />STATE OF TEXAS VISTA<br />Independence Parkway<br />MATCH LINE A<br />MATCH LINE B<br />INDEPENDENCE PARKWAY (120’ ROW)<br />END LID PROJECT<br />MATCH LINE B<br />INDEPENDENCE PARKWAY (120’ ROW)<br />
<ul><li> A scenic drive that tells the story of the corridor’s rich historical past utilizing epic art.
A No Impact Roadway utilizing a pavement section with a 24” deep gravel base for increased longevity as well as infiltration and storage.
A curb and gutter system with curb cuts that allow drainage into the proposed biofiltration swales.
Native vegetation to eliminate need for mowing, irrigation, and pesticides while providing rainwater filtration</li></ul>Proposed Solutions<br />
Cross Section<br /><ul><li> Cross-section designed to provide filtration, infiltration, and storage in order to allow for virtually zero discharge up to a 10-year event. Swales also provide conveyance for a 100-year event.
Each project component is designed for multiple functions:
Gravel road base also provides stormwaterinfiltration and storage
Bioswalesprovide stormwater filtration, conveyance, and storage
Check dams provide stormwater storage as well as platform for epic art</li></li></ul><li><ul><li> The bioswale filtration system consists of a swale drainage course with gentle side slopes, native vegetation, and check dams to manage all rainwater runoff generated within the corridor.
By utilizing proper soils, native vegetation and ponding of water within the check dams, a bioswalesystem provides pre-treatment of silt and pollutants from surface runoff prior to draining into the gravel infiltration storage bed. </li></ul>Bioswale<br />
<ul><li>Runoff from pavement drains through curb cuts to vegetated swales
Runoff within swale is detained by check dams along the length of the roadway
Runoff within swales infiltrates through gravel edge to a gravel storage area beneath the pavement, where it slowly infiltrates the subgrade and drains through the gravel and perforated pipe to the outfall.</li></ul>System Function<br />
<ul><li> Check dams are used to reduce erosion and gullying within the bioswale channel and to allow sediment and pollutants to settle.
Check dams shall be implemented on the basis of a 0.0022 ft/ft average slope and spaced 400 feet apart within the center bioswale. The spacing on the side bioswales would be 200 feet apart on average for both sides. </li></ul>Check Dams<br />
<ul><li> Once established, bioswale maintenance is minimal compared to typical drainage swales.
An established bioswale will require only seasonal maintenance compared to bi-weekly mowing required for typical drainage swales.
Native grasses and groundcovers are adaptive to local rainfall patterns, thus eliminating the need for an irrigation system once established.
Swale embankment inspection should be performed consistently during the rainy months of the year, with replanting of any bare patches where vegetation has been unsuccessful.
Sediment build-up within the bottom of the swale should be removed once it has accumulated to 25% of the original design volume.</li></ul>Bioswale Maintenance<br />
Epic art provides an opportunity through imagery to tell a story of the rich historical past that this area represents. The concept is to create a museum without walls along Independence Parkway<br />Epic Art<br />
By proposing a native plant palette that is relevant to the history of the region and battleground, we are encouraging the re-establishment of the historical landscape which will also provide an additional educational opportunity along Independence Parkway <br />Native Grass Mix:<br /><ul><li> Little Bluestem
Construction Cost<br /><ul><li> Standard Harris County roadway = $3.6 million/mile</li></ul>LID Improvements<br /><ul><li> Reduction of $675,500 is storm sewer improvements.
Cost for complete LID project = $4.1 million/mile for roadway and bioswales. Optional project costs include lighting, epic art, and signage.
Although upfront cost for LID road is greater than current standard County road, a significant cost savings will be realized in reduced maintenance cost over the life of the road.</li></ul>Cost Estimate<br />