Landscape Requirements in the City of Mobile

And their affects on the Dog River Watershed

Jason Kemple, Department of Earth Sciences, University of South Alabama, Mobile, AL 36688. Email: jkemple@comcast.net

Dog River Watershed has been deteriorating since growth began in Mobile. Construction of new houses, shopping complexes, and restaurants has made many of the surfaces impermeable, therefore allowing water to quickly enter a stream or retention pond. This causes erosion problems in Dog River’s tributaries. This research examines the landscape requirements for the City of Mobile and interprets how they either help or hurt Dog River. The City of Mobile’s Zoning Ordinance provides the law on landscape requirements within the city. Landscaping is crucial to watershed survival, especially in an area with so much rain. Other cities do not have such strict landscaping requirements as Mobile does, but it is very important that cities and the public understand the benefit that landscape requirements give to watersheds.

Keyword: Dog River, watershed protection, landscape requirements.

Introduction

The world’s largest cities are either facing, or will soon be facing a major crisis. The crisis is water. “A study by the World Bank and the Worldwide Fund for Nature found that a third of the world’s largest cities are almost entirely reliant on protected forests for clean drinking water” (Amodeo and Ball, 2003). Many people may not understand why vegetation, such as trees and plants, is so crucial to water, and ultimately to human life. One example is that vegetation along rivers, streams, and lakes protects people and places from flooding. Water is affected by gravity; it flows to the lowest spot it can find. The area in which all water flows to a certain location is the area’s watershed. Watersheds are very important to life. “Watersheds comprise the system of arteries that give life to the land” (Southerland, 2000).

Forests help preserve watersheds and keep water clean. However, due to the ever-increasing population, forests are sacrificed to development. Millions of trees all over the world are lost daily to construction, and many of these trees are important to the watershed they are in. During heavy rains in Caracas, Venezuela in 1999, the city and its suburbs were dramatically affected by flooding. Up to thirty thousand people lost their lives in areas where natural vegetation was replaced by poorly constructed barrios. Lying in Caracas’s center core is the Mount Avila National Park. This area was much less damaged. “The park’s intact natural system of dense vegetation cover was able to absorb much of the cumulative rainfall and prevent it from turning into a torrent of uncontrollable floodwater” (Holston, 2000).

Watersheds need to be saved. One way that cities have started doing this is by passing land ordinances that not only keep their city looking beautiful, but protect it as well. “Protecting watershed forests is no longer a luxury. When they are gone, the costs of providing clean drinking water to cities will increase dramatically” (Amodeo and Ball, 2003).

The Dog River Watershed is located from downtown Mobile (east of I-65) into West Mobile, outside of Mobile City limits (Fig. 1). It is a watershed that needs protection. Forty percent of the Dog River Watershed lies within city limits. The City of Mobile and its suburbs, including the Dog River Watershed, is growing at a very fast pace. Since most of the area east of I-65 is relatively flat, what would happen if we had a very wet summer? The more vegetation that gets taken down by construction in the Dog River Watershed, the more probable that major flooding could occur in this area. Lives could be lost because of cutting down vegetation. It’s just not worth it, and people need to know this.

The Dog River Watershed is a large area, and it gets wet in Mobile during the summer. By having trees, bushes, plants, and more natural vegetation, it helps control the water going into the river. The vegetation slows erosion down, and holds a great deal of water. According to the Zoning Ordinance of the City of Mobile, “landscaped areas serve to protect soil erosion; reduce the hazards of flooding; absorb carbon dioxide and supply oxygen” (Zoning Ordinance of the City of Mobile, 1967). These concepts are very important when dealing with watershed issues.

Landscape requirements have a great deal in common with Dog River and its tributaries. The public needs to know why it is important that we follow these rules that the city has implemented. Not only does the vegetation look nice, but it also helps control flooding, which is very important in Mobile. Due to the increase in construction in West Mobile, many surfaces are becoming impermeable and causing flood and erosion problems.

Research Question

I am going to inform the public on landscape requirements in the City of Mobile, and their effects on the Dog River Watershed. This is very important because many people do not know that within the city limits, there are laws that prohibit people from cutting down trees and laws that require a certain amount of landscaping (i.e. trees, bushes) per acre of land. Many people have the assumption that if it is on their property, they can do what they want with it. Within the city limits, this is not true.

Methods

The Zoning Ordinance for the City of Mobile gave me a great deal of information on land ordinances, why they are in place, and what the laws are. This is an excellent source of information because this is the book that states the law word for word on landscape requirements within the City of Mobile.

I was able to meet with David Daughenbaugh, the Urban Forestry Coordinator for the City of Mobile. Mr. Daughenbaugh provided me with information about the landscape ordinances that Mobile currently has enacted. He went into detail on the definition of landscape requirements, and how the Urban Forestry Department decides what type of landscaping construction site needs on their property.

Searching the journals that are held online by the University of South Alabama’s library, I was able to find references to other cities and countries and the problems they have had when it comes to watersheds or flooding. I also was able to get in touch with the City of Montgomery and find out their landscape requirements to compare them with Mobile.

Results

Although the Zoning Ordinance book does not specifically mention watersheds or watershed protection, the landscape requirements play a very important part in protecting watersheds, but more importantly in protecting yourself, your family, and your property. Although landscape requirements are exempt in residential zoning, all other types of zoning have to meet these requirements and it is crucial that they do.

As of 1993, twelve percent of the total building site of an area must be landscaped. This includes Heritage Trees, Overstory Trees, Understory Trees, and bushes/shrubs. Heritage Trees are any trees protected by the ordinance; a tree that is required under commercial construction and they become heritage trees at the time of planting. This also includes all trees located on city right-of-way, city parks, and historical districts. Overstory trees are any trees whose canopy, at maturity, will exceed 35ft. in height or higher. Examples include Sycamore, Maple, Magnolia and Live Oak Trees. Understory trees are trees whose canopy, at maturity, does not exceed 35ft. in height. These trees include Crepe Myrtles, Redbuds and Bradford Pears.

Sixty percent of the landscaped area must be on the building property between the building wall and the street. Aside from that, the building site must contain one Heritage or Understory tree for every thirty feet of the outside lot perimeter. Additionally, one understory tree is required for every 20 parking spaces on the property. If there is a site being built that does not contain enough “green space” for the trees needed, the owner is given the option of donating $200 per tree to a tree bank, which will be used to plant trees in other areas of the city.

During my internship with the Urban Forestry Department, I have seen many building lots that required at least forty to fifty trees. In a book published about Mobile, it was stated that many airline pilots call Mobile the “city under the trees”. This is very important, not only for having the city look beautiful, but for protecting the watersheds as well.

Many people are not aware that vegetation helps control flooding and erosion. These are major problems with Dog River. Because a tree is dropping too many leaves or has the wrong color flowers on it (which I have seen put before the Tree Commission), property owners want the trees taken down. Thankfully, the Tree Commission will not let a person take down a tree for such trivial reasons. And if they do accept a proposal to take down a tree, the owners must replace it. Figure 2 and Figure 3 show graphs from the City of Mobile’s Department of Urban Development. These graphs show important information on trees planted, saved, and how many trees went into the tree bank since 1992. Figure 3 breaks down the trees into their separate categories.

The City of Montgomery provided me with their Landscape Ordinances. I wanted to obtain these to compare Mobile’s ordinances with the City of Montgomery. According to James Center, Montgomery’s Land Use Controls Specialist, “the City of Montgomery’s Landscape Ordinance is based on the number of parking spaces. This is due to the fact that paved parking areas create the greatest amount of post construction runoff”. In other words, the City of Montgomery has landscape requirements based on the number of parking spaces on a site.

Discussion and Conclusion

The Zoning Ordinance for the City of Mobile provides landscape requirements which are vital to the city and our watershed’s health. James Center, Montgomery’s Land Use Controls Specialist stated, “Landscaping affects the rate flow and also water quality of water within watersheds”. When comparing Mobile’s landscaping requirements with Montgomery’s, it is clear to see that Mobile has more requirements than Montgomery.

This information is important in determining how strict Mobile’s landscape requirements are. Montgomery is somewhat like Mobile in respect to climate. However, their landscape requirements are solely based on the number of parking spaces. In Mobile, we take parking spaces into consideration also, adding one understory tree for every twenty parking spaces. But we also include the size of the property to determine how many trees need to be planted. Although Mobile’s landscape requirements are strict, it gives health to Dog River Watershed and other watersheds in the area.

The Department of Urban Development for the City of Mobile provided me with two separate graphs that illustrated the number of trees that have been saved, planted, or sent to the tree bank. This information is important because it lets the public know that by having these landscape ordinances is making a difference in the city. Since 1992, 37,552 trees have been planted. That is a very large number for a smaller city such as Mobile. It is no wonder why airline pilots call Mobile the “city under the trees”.

This information is also broken down into the types of trees planted. As you can see, since 1992, more overstory trees have been planted. Although the landscape requirements suggest this would happen, it shows the public that big, important trees are being planted as well.

With this information, the public should be well aware of why we have landscaping ordinances and the importance in following them. Without landscape requirements, the city would have less trees and more impermeable surfaces which would cause erosion of sediment into our rivers. Human life depends on water, and if our watersheds get polluted, so does our drinking water. This will only cause a rise in prices for the use of water since most of it will have to start getting filtered. This should intrigue the public as to what they can do to help save their watershed. The City of Mobile’s Land Ordinances protect all types of vegetation. These laws are not here to be picky, but they are here to save our city. It is laws like these, and the understanding of the public about watersheds that will help protect ourselves and our families in the future.

References

Amodeo, C. and Ball, M. 2003. Watershed Protection vital for world’s cities. Geographical 75(12): 15.

City Council of the City of Mobile. 1967. Zoning Ordinance of the City of Mobile.

City Council of the City of Montgomery. 2000. Zoning Ordinance of the City of Montgomery.

Holston, M. 2000. Where has all the Water Gone? Americas 52(3): 32.

Liban, C. 1998. Non-Point Source Pollution. National Forum 78(3): 7.

Lindsey, G. 2003. Environmental Planning. Journal of the American Planning Association 69(1): 101.

No Author. 2003. Not Out of the Woods. Economist 366(8315): 73.

Shultz, S. and Saenz, F. 1998. Linking People to Watershed protection planning with a GIS: A case study of a Central American Watershed. Society and Natural Resources 11(7): 663.

Southerland, R. 2000. Watershed Protection: Help is a click away. American City & Country 115(7): 6.