The Impact of Construction on Dog River Watershed

Doni E. Thompson, Earth Sciences Department, University of South Alabama, Mobile, Al 36688. E-mail: det601@jaguar1.usouthal.edu. The Dog River Watershed consists of several streams and drainage ditches that drain the Mobile, Alabama area and empty into Mobile Bay. More homes and businesses are being constructed in the area to support the growing population. This construction has a negative effect on the watershed. The lack of vegetation, due to land clearing, leads to erosion. Building materials are also washing into the rivers and tributaries. This has a huge effect on stream and river health. Repeat photography is used to determine how long these construction sites affect the watershed. Older photographs were studied from 1997 to 2008. New photographs were taken of ongoing construction sites. These sites included over twenty residential, commercial, and roadway construction sites. The photographs were used to determine how long the sites affected the watershed. These sites cumulatively impact the health of the Dog River and its tributaries. The sites may be short term, but the impacts are huge and new construction sites are always opening. The area takes a long time to recover. The length of time is crucial to overall health of the watershed. This study provides education to the public and may stimulate ideas for improvement. It also brings much needed attention to poor construction practices.

Keywords: Dog River Watershed, repeat-photography, construction

Introduction

The Dog River Watershed consists of several streams and drainage ditches that

drain the Mobile area and empty into Mobile Bay. It is also the key to estuarine health in

Mobile Bay. Forty percent of the Dog River Watershed is in Mobile County and the other

sixty percent is within the Mobile city limits (Fearn, 2009). All of Mobile County is

growing in population. The county grew by over 25,000 people between 1990 and 2007

(U.S. Census Bureau). As the population continues to grow, so do areas of construction.

More homes and business are being built in this area to support the growing population.

Construction can have a negative effect on the watershed. Some of these may be short

term, but some may be much longer. Poor land development practices have a longer term

effect on the Dog River Watershed. The lack of vegetation, due to land clearing, may lead

to erosion, which is simply the movement of dirt, sand, rocks, and other sediment. Rain

water may cause sediments and building materials to flow off of a hillside into streams

and tributaries. This affects the health of the river and streams.

By using repeat photography, it is easy to determine how specific areas contribute

to the degradation of the Dog River Watershed. Repeat photography refers to two or

more pictures taken from the same place with the same field of view, ideally with

cameras possessing the same focal characteristics, but at different times (Hanks, 2006). It

is often used to show change in geographic features over time. Whenever early

photographs are repeated, they become elements of continuous record (Skovlin, 1995).

Repeat photography shows approximately how long a construction site may affect the

area.

Research Question

How long do residential, commercial, and construction sites impact the Dog River

Watershed? Identifying this may lead to more stern enforcing of laws for construction

companies. It will also better educate the community about the impacts that construction

areas have on the Dog River Watershed.

Methods

Repeat photography is a simple research method that provides great results. First,

past photographs, taken by previous geography students, of the Dog River Watershed

were studied. Past photographs of construction areas in both residential and commercial

areas were located. Twenty locations were chosen for this research, all within Mobile’s

current city limits. The photographs were studied to see how the construction and

surrounding areas changed throughout the years and what kind of impact they show.

Areas are located on a map and photographs were taken at each of the locations. They

needed to be taken from the same field of view or angle as the original photographs,

which allowed better interpretation of changes to the areas. The period of time that the

watershed is degraded can be determined for commercial, road, and residential areas.

Field notes were taken to record any changes, the condition of the area and nearby

waterways, and any problems experienced while collecting research materials. A report

the overall changes and effects to the area is given. Repeat Photography is the best

research method to provide answers on this subject.

Figure 1: The map shows all of the study area. The orange dots represent each location visited to repeat photographs. Results

The results of this study are very interesting. Using repeat photography, it is easy

to see that many former construction sites still have issues. Years later, many of the

construction sites still play a role in the degradation of Dog River Watershed. Most of the

sites that showed significant poor construction practice still have problems now, with

erosion still being the dominant issue in the areas. A key example is a gas station located

at Azalea Road and Michael Boulevard (Fig. 2 and 3). The construction was underway in

January of 1997 and showed poor practices from the beginning (Appendix A). Twelve

years later, dirt and sand is still eroding from the area and silt is seen in the ditches

flowing downhill toward Montlimar Canal. Another example is the Lowe’s on Airport

Figure 2: 1997 image of Chevron Figure 3: 2009 image of Chevron

Boulevard and Schillinger Road, in construction during 1999 (Appendix D). The

structure sits at the top of a hill. At the time of construction, improper use of silt fences

led to the erosion from the parking lot. At the present time, the eastern hillside is still

experiencing erosion very near Milkhouse Creek. Another example is a church located on

Schillinger Rd that was built on a hillside (Appendix Q). They had to cut into the hill and

this area still has major erosion issues. Day Springs Baptist Church on Cody Road is very

similar (Appendix S). All the hillsides are eroding away and the retention ponds are full

of silt. During this research, very few sites with previous poor construction practices were

without any problems currently. However, some were surprising. The Hampton Inn and

Suites on Interstate 65 Service Road was one of these sites (Appendix J). Poor

construction with excess erosion was underway in 2006. Presently, the site is well

maintained and shows no signs of erosion or any other construction related issues. The

sites with good construction practices seemed to have fewer problems then and show no

land disturbances presently. Other examples include a business on Montlimar Road and

Legacy Village on Dauphin Street (Appendix B and T).

There were also areas that seemed to have once been cleared for construction.

There is a cleared site behind Wal-Mart on Schillinger Road, and it is unknown how long

the area has been cleared (Fig. 4 and 5). However, some photographs of the cleared area

date back to 1999 and 2003. There is no evidence of any preventative measures to stop

erosion. There is also no sign of any structures being built or land for sale. Access to the

rear of the site is not open, but the farthest area in view is less than a third of a mile uphill

from Milkhouse Creek (Appendix I). Some areas, such as a section of land behind

Knollwood hospital, were once cleared with no signs construction. The area experienced

erosion problems three years ago, but is now overgrown with vegetation (Appendix M).

An area around the former Cock of the Walk restaurant seems to have been cleared also

(Appendix K). Much of the sand flows into Halls Mill Creek during rain events. This area

was once run by the Army Corp of Engineers and has not been cleaned up. There is a lot

of erosion and old silt fence material in the area.

Figure 4: Behind Wal-Mart on Schillinger Rd Figure 5: Behind Wal-Mart on Schillinger Rd in 2003 in 2009

Another issue is silt fencing and other construction material being left behind after

the land has healed. The above mentioned area near Knollwood hospital is a good

example. Many silt fences were left behind even though they are no longer needed. They

are now torn and littering the area. This is seen in several other places, including the

Target shopping center on Schillinger Road (Appendix F). At this site, the only thing left

is the short wire fencing and the material is now ripped and torn off. It serves no purpose

and needs to be removed, because it only causes more pollution to the area. Silt fences

should be removed when they are no longer needed or required (Caltrans, 2003). Other

sites, such as Shadow Creek sub-division on Sollie Road, never finished construction

(Appendix N). They left a lot of materials and debris behind, but never built anything

other than roads.

It is difficult to say whether commercial or residential construction sites have a

longer effect on the watershed. Many commercial structures are built quicker, but the

land takes longer to heal, if it heals completely at all. Individual homes tend to be built

fairly quickly and have less long term effects. An example of this is the two homes in

Wimbledon Park sub-division (Appendix C). They were built quickly and did not affect

Eslava Creek for a long period of time. The sub-division is now running out of space to

continue building. However, some communities and sub-divisions may have long term

effects, because many homes are built in sub-divisions. Many of them continue to expand

through out several year periods, so the area as a whole may have longer effects than one

commercial site. Dawes Lake Estates is a good example of this (Appendix P). The first

homes were built in the late 90s. The sub-division has expanded farther since then and

new homes are being built on the lake using poor practices currently. Another example is

Stone Hedge sub-division (Appendix O). Many homes have been built here in the past

several years and some are still being built now. Some of these sites have poor

construction practices that affect Second Creek, which runs directly through this sub-

division. Another site is the Brookside Retirement Community at the intersection of

Milkhouse Creek and Cottage Hill Road (Appendix G). This community has been

expanding for over ten years. The areas recover well from the poor construction, but it is

constantly affecting the watershed. They need to do more to protect Milkhouse Creek.

Minor road construction tends to be short lived. Most of the companies seem to

use decent construction practices more recently. An example is the road construction on

Government Street near Interstate 65 (Appendix H). It was a poor construction site, but

recovered quickly. Another example is the service road near I-65 and Halls Mill Road

(Appendix L). The site had poor construction practices also, but recovered well in less

than a year.

Discussion

There was some trouble faced while doing this research. Some previous photos

dated back to 1997. Over any amount of time, land and vegetation can change

dramatically. In several cases, vegetation had grown so much that repeating the photos in

some areas was nearly impossible and even dangerous (Fig. 6 and 7). In some instances,

Figure 6: Vegetation in 1997, behind Wal-Mart Figure 7: Same location in 2009

fences were put up to enclose property, making it impossible to reach the previous

construction sites. Some sites are now surrounded by other structures, making it hard to

get the same camera angle. Updated photographs were originally taken in early March.

Due to technical difficulties, the process had to be repeated again in mid April. In that

small time period, much of the vegetation had grown. Many trees had new blooms and

new leaves, which prevented many photos from being replicated as easily as the previous

attempt.

Other problems included construction companies having issues with photos being

taken of there current sites. At one particular site, pictures were not allowed of a

developing area connected to a retirement community. Unless there is something to hide,

there should not be any issues.

Conclusion

All in all, new homes and businesses must be built to support the growing

population and people moving away from the metro area. There is constantly new

construction through out the area and the sites as a whole contribute to the degradation of

the Dog River Watershed. It is difficult to say how long the area has problems, because it

is constantly being affected. The sites cumulatively affect the health of the Dog River and

its tributaries. Sedimentation and erosion contribute significantly and some sites had this

problem in the beginning and it is still ongoing. Also, the poor construction sites built on

hills have the worst problems currently. The hillsides are still eroding and taking longer

to heal. The poor construction sites that were built on flat areas tended to heal quickly. To

put an actual time frame on it is impossible. Good construction practices are a necessity

to improve and restore the quality of the watershed. It is important for the people who

live and work in these areas to understand how the area is affected by the construction

sites. Strict laws need to be in place for the construction companies and need to be

heavily enforced. Preventative action needs to be taken at all times to reduce sediment

that flows into the river. Educating the public may also stimulate new ideas for improving

construction practices.

These photographs, old and new, will provide excellent records for the future. The

new photos will continue the sequence for further research and comparison. This project

can be repeated often to provide a better understanding of the effects the construction

sites have.

References

Alabama Department of Environmental Management. 1994. A Survey of Dog River Watershed. Accessed on 28 March 2009.

Alabama Department of Environmental Management. 1995. A Survey of the Dog River

Watershed Second Year’s Findings. Accessed on 28 March 2009. Caltrans. 2003. Construction Site Best Management Practices Manual. Section 4, Silt

Fence, SC-1. Accessed on 16 April 2009. Cerney, Dawna L., J. Ronald Eyton, David R. Butler. 2008. Assessing Landscape Change

in Waterton Lakes National Park, Canada, Using Multitemporal Composites Constructed from Terrestrial Repeat Photographs. Geocarto International, 23: 5,347-371. accessed on 26 February 2009.

Fearn, Mimi. Dog River Clearwater Revival. Last updated on 2 January 2009. Accessed

on 26 February 2009. http://www.usouthal.edu/geography/fearn/DRCR.htm Hanks, Thomas C. Repeat Photography, Virtual Repeat Photography, and Earth Surface

Change in the Photographic Era. Copyright 2006. Accessed on 26 February 2009. http://gsa.confex.com/gsa/2006AM/finalprogram/abstract_113487.htm

Previous Construction Photos: provided by all field work in geography classes between

1997 and 2008. All photos were taken in the Dog River Watershed. Accessed between February 2009 and May 2009.

Skovlin, Jon M., Jack Ward Thomas. 1995. United States Department of Agriculture.

Interpreting Long-Term Trends in Blue Mountain Ecosystems from Repeat Photography. Gen. Tech. Rep. PNW-GTR-315: p.1-15. Accessed on 26 February 2009.

United Stated Census Bureau. Population Finder. Accessed on 26 February 2009.

http://factfinder.census.gov/servlet/SAFFPopulation?_event=ChangeGeoContext&geo_id=05000US01097&_geoContext=&_street=&_county=Mobile&_cityTown=Mobile&_state=&_zip=&_lang=en&_sse=on&ActiveGeoDiv=&_useEV=&pctxt=fph&pgsl=010&_submenuId=population_0&ds_name=null&_ci_nbr=null&qr_name=null&reg=null%3Anull&_keyword=&_industry=

Appendix A: Chevron at Azalea Rd. and Michael Blvd

1997 2009

1998 2009

Appendix B: Technical Suite on Montlimar Dr.

1997 2009

1997 2009

Appendix C: Wimbledon Park Neighborhood on McGregor Rd.

2004 2009

2004 2009

2004 2009

Appendix D: Lowe’s at Airport Blvd. and Schillinger Rd.

1999 2009

1999 2009

Appendix E: Christ United Methodist Church at Grelot Rd. and Hillcrest Rd

2003

2003 2009

Appendix F: Target shopping center on Schillinger Rd.

2001 2009

2001 2009

2005 2009

Appendix G: Brookside Retirement Community at Cottage Hill Rd.

1999 2009

2005 2009

1999 2009

Appendix H: Government St. near I-65

2003 2009

Appendix I: Behind Wal-Mart on Schillinger Rd.

1997 2009

2009

Appendix J: Hampton Inn on I-65 service rd.

2006 2009

2006 2009

Appendix K: Old Cock of the Walk Restaurant on Halls Mill Rd.

1998 2009

2000 2009

2003 2009

Appendix L: Government service rd. near Halls Mill Rd.

2003 2009

Appendix M: Former site of Mitchell Cancer Institute on Knollwood Rd.

2006 2009

2006 2009

Appendix N: Shadow Creek Sub-division on Sollie Rd.

2001 2009

1999 2009

2001

Appendix O: Stone Hedge sub-division on Grelot Rd.

1998 2009

2009 2009

Appendix P: Dawes Lake Estates on Dawes Rd.

1998 2009

1998 2009

Appendix Q: Church on Schillinger Rd. just south of Cottage Hill Rd.

2002 2009

2002 2009

Appendix R: Chevron at Schillinger Rd. and Three Notch Rd.

2001 2009

2001 2009

Appendix S: Day Springs Baptist Church on Cody Rd.

2003 2009

2003 2009

2009 2009

Appendix T: Legacy Village on Dauphin Street near I-65

2006 2009