Flooding - New Infrastructure for Land Development
Looking at some of the different videos and news conferences that I've seen recently, I've noticed that a lot of the drainage issues are with older subdivisions that were designed using outdated design standards and criteria. You'll notice that some of the existing residential neighborhoods have shallow drainage swale systems, which may poorly convey water to an ultimate discharge point such as; a lake system, canal, river, or dry detention area. One of the things that I think is important, is to research and retrofit some of these older communities and roadway systems, bring them up to date with the current design standards, where they can provide water quality and comply with the current State's stormwater management system requirements, and also provide the necessary flood protection.
Ultimately, we don't want rain coming into our homes or businesses. What most people don't realize is that during the heavier intense rain storms the local roads WILL flood. A large majority of the roadways, including local roads, are designed to actually handle and store water temporarily. The roadway drainage systems should bleed-down within a short period of time, typically within a few hours or less. The reason for that is, many times it is too cost prohibitive to design a system that will leave the roads or swales completely dry during large rain events.
What we can do is go in and look at retrofitting the facilities to reduce some of the impervious areas. Impervious areas include anything that falling water from the sky would hit and produce runoff including; a house, building, parking lot, driveway, sidewalk, or anything where the water would sheet away. As you can probably imagine, in a city or a highly urbanized area, the larger rain storm events would sheet more water away thus causing major flooding. That's why by reducing impervious areas you then reduce the amount of water that sheet's away and therefore minimize flooding. Some examples to help address these situations are;
The above items are a few of the examples of low impact development examples. Ultimately you want to design your projects smarter than the way we've designed projects over the past 50 to 100 years. In conventional land development, a developer would clear a piece of property first, build a strip mall or shopping center, wrap it with a bunch of parking lots, and put a small drainage system in place to help minimize the drainage or storm-water running back into the project. Now we need to think a little smarter!
Some of our local resources, such as water, can be at a premium. You can travel to other places or countries where there is little water or rainwater. Just letting rainwater hit the impervious areas, sheet flow into the rivers and streams, that's a large percentage of water that typically just dumps into the rivers and oceans. It would be nice to capture and utilize some of that water and further reducing the demand from our municipal water systems. For one, your paying for water. If you can capture water from the sky, that is less that you have to pay for and help save or even repair the aquifer.
There's some places where you have to get permits to withdraw from a aquifer. And there's some aquifers that are polluted to the point that you can't use the water for drinking water. Plus, let's add the fact that some of the aquifers are very limited with the ability to extract water at all. Sooner of later, we're gonna realize how finite a resource water is and low impact development is one of the techniques that I see being an important turn around for engineers, architects, designers, professionals, and developers. Professionals need to start designing their facilities in a way where they can design parking lots that include shading for the patrons to have shaded areas, whether it's through the process of using trees, parking garages, or solar panel covers. In lieu of using asphalt pavement, you can use concrete or some kind of lighter coating that would tend to reflect the heat away as opposed to absorbing it. Consider using pervious pavement or pavers, or in some cities you can utilize gravel; however, some of the codes don't allow that.
Landscaping is critical! Plant trees, but plant in the right place and not under power lines. Be sensitive to the proximity to larger trees that are closer to structures. Living in Florida, we have hurricanes; however, regardless of where you live, you will want to be careful that trees don't hit structures. At the same point, having a tree fairly close to a building, in certain locations such as southern or western exposure, can help provide shading. Shading would reduce your heat load inside facilities, helping to improve air conditioning consumption by not running as long, while also saving on energy bills. These are some examples of low impact development external to the building. A developer should also coordinate with their architect or designer, so they can work through some other energy saving elements inside a facility.
Rainwater harvesting was touched on a bit, and I feel that it's really critical. You can use a rainwater system such as small rain barrels. If your a homeowner, you can place a rain barrel at each gutter location. You can use the rain water to water a small herb garden. If you have a small water feature or pond, you can use the rainwater makeup the loss of pond water. Another example that you can use rainwater for is a swimming pool. Here in Florida, we have a high evaporation rate, so we have a tendency to use makeup water. With using well water to fill a pool, the pool typically requires some chemicals and some additives to bring it into balance. Rain water typically works out really well for makeup water and normally does not require a lot of chemicals to balance the water.
There's a lot of things you can use the rainwater harvesting system for. I've briefly touched on low impact development with a few minor components that we've seen our development projects. Should you have any questions, or possibly want to discuss other ways that we can improve the infrastructure of land development, feel free to contact us.
David L. Phillips, P.E.
LEED AP BD+C | President
Sustainable Engineering & Design, LLC
Consulting Civil Engineers
P.O. Box 2247 | Vero Beach | FL | 32961-2247
Office: 772-257-3032 | Fax: 772-257-3033 | Cell: 772-538-7514
dp@SED-eng.com | www.SED-eng.com
Call us today; Our team is ready to help you!
Ultimately, we don't want rain coming into our homes or businesses. What most people don't realize is that during the heavier intense rain storms the local roads WILL flood. A large majority of the roadways, including local roads, are designed to actually handle and store water temporarily. The roadway drainage systems should bleed-down within a short period of time, typically within a few hours or less. The reason for that is, many times it is too cost prohibitive to design a system that will leave the roads or swales completely dry during large rain events. What we can do is go in and look at retrofitting the facilities to reduce some of the impervious areas. Impervious areas include anything that falling water from the sky would hit and produce runoff including; a house, building, parking lot, driveway, sidewalk, or anything where the water would sheet away. As you can probably imagine, in a city or a highly urbanized area, the larger rain storm events would sheet more water away thus causing major flooding. That's why by reducing impervious areas you then reduce the amount of water that sheet's away and therefore minimize flooding. Some examples to help address these situations are;
- To retrofit existing projects to reduce the impervious areas.
- Look at other alternatives such as bio-swales. You can actually design bio-swale systems in lieu of draining into a curb inlet or curb gutter. This in turn will provide improved water quality and you are not dumping water directly into canals, ditches, lakes, streams, and oceans. Remember, everything ultimately drains into the ocean!
- Rain gardens are also a great best management practice, which you may hear more about. People are starting to develop and utilize these attractive systems.
- Rainwater harvesting systems capture rainwater and use it to help supplement some of your potable water, flushing toilets, supplementing some of your irrigation needs, and ultimately reduces some of the water that would normally be extracted from the aquifer.
The above items are a few of the examples of low impact development examples. Ultimately you want to design your projects smarter than the way we've designed projects over the past 50 to 100 years. In conventional land development, a developer would clear a piece of property first, build a strip mall or shopping center, wrap it with a bunch of parking lots, and put a small drainage system in place to help minimize the drainage or storm-water running back into the project. Now we need to think a little smarter!
Some of our local resources, such as water, can be at a premium. You can travel to other places or countries where there is little water or rainwater. Just letting rainwater hit the impervious areas, sheet flow into the rivers and streams, that's a large percentage of water that typically just dumps into the rivers and oceans. It would be nice to capture and utilize some of that water and further reducing the demand from our municipal water systems. For one, your paying for water. If you can capture water from the sky, that is less that you have to pay for and help save or even repair the aquifer.
There's some places where you have to get permits to withdraw from a aquifer. And there's some aquifers that are polluted to the point that you can't use the water for drinking water. Plus, let's add the fact that some of the aquifers are very limited with the ability to extract water at all. Sooner of later, we're gonna realize how finite a resource water is and low impact development is one of the techniques that I see being an important turn around for engineers, architects, designers, professionals, and developers. Professionals need to start designing their facilities in a way where they can design parking lots that include shading for the patrons to have shaded areas, whether it's through the process of using trees, parking garages, or solar panel covers. In lieu of using asphalt pavement, you can use concrete or some kind of lighter coating that would tend to reflect the heat away as opposed to absorbing it. Consider using pervious pavement or pavers, or in some cities you can utilize gravel; however, some of the codes don't allow that.
Landscaping is critical! Plant trees, but plant in the right place and not under power lines. Be sensitive to the proximity to larger trees that are closer to structures. Living in Florida, we have hurricanes; however, regardless of where you live, you will want to be careful that trees don't hit structures. At the same point, having a tree fairly close to a building, in certain locations such as southern or western exposure, can help provide shading. Shading would reduce your heat load inside facilities, helping to improve air conditioning consumption by not running as long, while also saving on energy bills. These are some examples of low impact development external to the building. A developer should also coordinate with their architect or designer, so they can work through some other energy saving elements inside a facility.
Rainwater harvesting was touched on a bit, and I feel that it's really critical. You can use a rainwater system such as small rain barrels. If your a homeowner, you can place a rain barrel at each gutter location. You can use the rain water to water a small herb garden. If you have a small water feature or pond, you can use the rainwater makeup the loss of pond water. Another example that you can use rainwater for is a swimming pool. Here in Florida, we have a high evaporation rate, so we have a tendency to use makeup water. With using well water to fill a pool, the pool typically requires some chemicals and some additives to bring it into balance. Rain water typically works out really well for makeup water and normally does not require a lot of chemicals to balance the water.
There's a lot of things you can use the rainwater harvesting system for. I've briefly touched on low impact development with a few minor components that we've seen our development projects. Should you have any questions, or possibly want to discuss other ways that we can improve the infrastructure of land development, feel free to contact us.
David L. Phillips, P.E.
LEED AP BD+C | President
Sustainable Engineering & Design, LLC
Consulting Civil Engineers
P.O. Box 2247 | Vero Beach | FL | 32961-2247
Office: 772-257-3032 | Fax: 772-257-3033 | Cell: 772-538-7514
dp@SED-eng.com | www.SED-eng.com
Call us today; Our team is ready to help you!
Treasure Coast Branch Chair
USGBC South Florida Chapter
Committee Member
St. Lucie County School Board Energy Advisory Committee
Member
Florida Green Building Coalition
Board Member
Harvest Food & Outreach Center
Posted by Sustainable Engineering Design at 11-08-2011 
Categories: Going Green, Sustainable Engineering
Tags: flooding flood waters low impact development rainwater runoff storm water drainage system rainwater harvesting rain garden bio-swale bio swales
Categories: Going Green, Sustainable Engineering
Tags: flooding flood waters low impact development rainwater runoff storm water drainage system rainwater harvesting rain garden bio-swale bio swales
Comments