Miami

Miami: Climate

Miami’s client is similar to Houston in several ways. It has one of the highest

levels of rainfall of any major U.S. city. It receives an average of 58.6 inches of

rain per year. Statistically it is the most likely major city to be hit by a

hurricane in the world.

Miami: Geography

The city of Miami is one of the most densely populated cities in the United

States. The city itself encompasses 354.5 square miles an contains Miami

Dade county encompasses 35.4 square miles and contains nearly 5.4 million

residents. The city is located on the coast, making it vulnerable to hurricanes.

To combat this there are several natural and man made barrier islands.

Miami: Map

Miami: Geography

The city’s drainage is heavily affected by the natural conditions around the

city. Like Houston, Miami is located on a very flat piece of ground. The

ground never rises above 40 feet above sea level and goes as low as sea level.

The average elevation of the city is 6.2 ft above sea level. Because of its high

water table, it is not possible to dig below 15 to 20 without hitting water.

Because of this there is no subway system in Miami.

Miami: Local conditions

Miami is much stricter than Houston in its development and building

regulations. All development must take place above the Flood Criteria

Elevations defined as the higher of the 10 year, 1 day ground water elevation

or the 5 year 1 week ground elevation plus 18 inches. This elevation is

determined by the septic tanks that are very common in Miami-Dade. The

septic tank drains are commonly placed at 18 inches below grade, this

prevents overflowing. The flood evaluation has not been re-evaluated in

nearly 20 years.

Miami: Drainage/Rainfall

Miami: Storm systems

Miami Storm water Systems:

Major Systems: These systems can handle storm waters over the 10 year limit

approaching the 100 limit. These are usually main line underground piping

and open water channels.

Minor Systems: These systems are required to be able to handle up to and

including a 10 year storm. These are a combination of below ground sewers

and four lane roads for ten year storms, and two lane roads for five year.

Miami: Storm systems

Positive Drainage: Direct drainage into open bodies of water. This is the least

acceptable form of drainage since it is more likely to over flood.

Onsite Retention: This is the most desired strategy. It can be implemented in

several ways including: surface infiltration through grassy swales,

underground seepage such as exfiltration trenches, and retention ponds.

Dade county encourages 1 inch of retention.

Miami: Storm water

Miami: Diagrams

Dry Detention BasinShallow Grassed Swale

Miami: Storm systems

Commercial and industrial must provide at least ½” of dry detention or

retention.

Projects having greater than 40 percent impervious cover and discharge into

receiving waters must provide at least ½” retention.

All residential and commercial storm water management systems are

required to withstand at least the 5 year flood.

Bibliography

Information:Chin, David A. “An Overview of Urban Stormwater= Management Practices in MiamiDade County, Florida.”http://www.ci.miami.fl.us/cms/

Images:Miami-Dade Aviation Department: Storm Water Systemhttp://www.mapquest.com/444444http://en.wikipedia.org/wiki/Miami