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2.0
HAZARD IDENTIFICATION FOR OUACHITA PARISH Geography Ouachita Parish is located in the northeastern region of Louisiana and is divided into an eastern and western half by the Ouachita River. The Parish is bordered by Lincoln Parish, Jackson Parish, Caldwell Parish, Richland Parish, Morehouse Parish and Union Parish. Ouachita Parish contains four incorporated communities: the City of Monroe (Parish Seat), the City of West Monroe, the Town of Richwood, and the Town of Sterlington (See Figure 2.1, Ouachita Parish Map). The total land area within the Parish is approximately 611 square miles. Population The 1990 census reports the Ouachita Parish population at 142,191 people with 50,518 households. The estimated population for 1998 is 146,979 people. Ouachita Parish has a projected population of 158,590 people for 2000, an increase of 10.3% since 1990. Transportation The major transportation arteries within
Ouachita Parish include Interstate Highway 20, U.S.
Highways 165 and 80 and Louisiana Highways 15, 34, 139
and 143 (See
Figure 2.1, Ouachita Parish Map).
These roadways are significant evacuation routes for
Ouachita Parish, as well as surrounding parishes and counties
during a state of emergency.
A highway loop that will connect existing highways
surrounding Monroe, West Monroe and Richwood was evaluated in
a Major Investment Study (MIS) completed in August of 1999.
The MIS proposed a route for such a loop, which is
illustrated in Figure 2.1.
Further evaluation is now underway and sources of
funding are being explored.
Figure 2.1: Ouachita Parish Map
Topography The topography of Ouachita Parish ranges from flat floodplain east of the Ouachita River to rolling hills on the west side of the river. Elevations within the Parish range from 30 feet National Geodetic Vertical Datum (NGVD) along the Ouachita River and to the east to approximately 260 feet NGVD on the western side of the parish. The Ouachita River, which flows south and divides the Parish, originates as a tiny mountain stream in the Ouachita Mountains of central Arkansas. The Ouachita River joins the Tensas and Little Rivers to form the Black River about 60 miles to the south of the Ouachita Parish in Jonesville, LA. The river spans approximately 600 miles. Only the portion of the river that lies between the Arkansas-Louisiana state line and the north bank of Bayou Bartholomew is considered a Scenic River (which is all north of Ouachita Parish). Bayou Lafourche and Little Bayou Boeuf make up the eastern border of Ouachita Parish. Although Ouachita Parish only covers 611 square miles, more than 15,000 square miles of land drains into the Parish via the Ouachita River and its tributaries. This means that >96% of the water that the Ouachita River drains fell as precipitation outside Ouachita Parish. Out of that 15,000 square miles, approximately 2,700 square miles of land is drained by tributaries that enter the Ouachita River within Ouachita Parish. Figure 2.2 compares the relative size of the Ouachita drainage basins to surrounding drainage basins.
The convergence of these tributaries along with the 12,944 square miles of land that have already been drained by the Ouachita River when it enters the Parish results in the potential for significant flooding. Figure 2.3 shows the approximate drainage areas in square miles for the Ouachita River and Bayou Lafourche along with all of the major streams that flow into them within Ouachita Parish.
Climate The climate of Ouachita Parish is greatly influenced by the Gulf of Mexico, which gives the area a semitropical marine character. During the fall, winter and spring, heavy rainfall, hail and wind can result from frontal storms caused by the interaction of warm, moist air from the Gulf and cold, dry air from cold fronts approaching from the northwest. Intense convective storms triggered by daytime heating and gulf moisture can occur in the summer time. Even though this parish is positioned about 200 miles from the Gulf Coast, hurricanes and tropical storms can still pose a significant flooding threat. Sometimes as tropical storms and hurricanes move inland, they to lose strength and move slower, resulting in more rain to be dumped over a specific area. According to National Weather Service records, Ouachita Parish has averaged about 1 tornado per year over the past 30 years. The Parish has an average rainfall of 67.2 inches per year and the average temperature ranges from 430F in the winter to 830F in the summer. The average January minimum temperature for the past 30 years is about 330 and the average July maximum temperature for the past 30 years is about 920. January and July are typically considered to be the coldest and hottest months respectively. Economics farmland and timber. The floodplain in the eastern half of the parish provides fertile soil for agriculture. About 23% of the parishes land is cultivated crop land. The number of farm related jobs is difficult to tabulate because farm labor is seasonal and often temporary. The hilly terrain of the western half of the Parish provides optimum growing conditions for pine trees. Ouachita Parish comprised about 2% of Louisiana total timber production in 1998, but only comprises 1% of the state The largest single employer in Ouachita Parish remains the Ouachita Parish School System, with 2,150 employees in 1996. Health care services have become one of the largest employment sectors in the Parish. Table 2.1 shows the top ten employers of Ouachita Parish in terms of number of employees. The Parish currently enjoys a 4.0% unemployment rate as compared to a statewide rate of 5.2% and a national rate of 4.1%.Table 2.1: Major Employers of Ouachita
Parish
History of Ouachita Parish Taken from OPPJ Web Page
In 1785, Fort Miro was built on the banks of the Ouachita River, where the Courthouse presently stands today in downtown Monroe. Fort Miro was named for the Spanish Governor General of New Orleans, Don Estefan Miro, who appointed Don Juan Filhoil as Commandant of the Post of Ouachita, later renamed Fort Miro. In 1805 Fort Miro became a town. It was Don Juan Filhoil who donated land to be used forever as the seat of justice, the land on which today's Courthouse now stands. During this time a legislative
council was established in New Orleans to govern this new
territory and 19 counties were created.
They were later renamed parishes, because the
boundaries match the ecclesiastical parishes of the Catholic
Church, thus the Churches parishes became the units of local
government in the territory of Orleans.
With Fort Miro as its center, Ouachita was among the
original 19 parishes. At
first they were governed by an appointed Judge and Justice of
the Peace, 12 people were appointed to serve with the judge
and they were called a jury. The government of the territory of Orleans charged the jury
with responsibility to execute the concerns of the interior
and local police and administration of the parish. In 1810, the juries were renamed
the Police Assembly of the parish.
The members were then elected and in 1811 the Police
Assembly was officially renamed the Police Jury.
The judges and justices of the peace were slowly phased
out of the new government and the Police Jury became the
official governing body. Ouachita Parish received its name from the Ouachita Indians, a member of the Caddo Indian Confederation. Inside the walls of Fort Miro, a log cabin was constructed as the first Courthouse. In 1831, a brick Courthouse was built, only to be burned to the ground by Union soldiers, in 1863. A third Courthouse was built in 1868 and it too was destroyed by fire in 1882. Ouachita Parishes a year later. In 1944, it was demolished and the present Courthouse was built. Over the years, the
Police
Jury form of government developed into a
legislative and administrative body which passes ordinances
and resolutions, establishes programs, and sets policy.
As an administrative body, it prepares an annual
budget, hires personnel, spends money, and negotiates
contracts. The
Ouachita Parish Police Jury elects a president from among its
jury members. There are six members of the Ouachita Parish Police Jury,
representing six geographic areas (illustrated in Figure 2.1).
These areas are called districts, named districts A
through F. Police
Jury districts include people living inside the cities of Monroe, West Monroe, Sterlington, and Richwood. Flooding
History Taken
from FEMA Flood Insurance Study
The Ouachita River was a major flooding source to the parish prior to the construction of a floodwall and levee network in 1934. Ouachita Parish Also passed regulations designed to promote safe development and minimize flood losses (Appendix C), however, flooding is difficult to predict. The 1991 flood, which was at a stage of 50.5 feet, or 81.9 feet NGVD, was the highest recorded flood. The 100-year flood at a stage of 53.0 feet, or 84.4 feet NGVD, is 2.5 feet higher than the 1991 flood and 2.58 feet higher than the 1945 flood. Portions of the parish are subject to backwater flooding from the Ouachita River, while even larger areas are threatened when discharges in the Ouachita River exceed those used in the design of the existing levee system. The Chauvin Bayou/Canal L-11 and Youngs Bayou floodplains are subject to backwater flooding from Bayou LaFourche. Development in the Bayou LaFourche floodplain proper is primarily agricultural, with much of the area utilized for timber growth. Developments in Chauvin Swamp east of U.S. Route 165 have experienced flooding problems during the past few years. In December 1982, the Monroe FAA
Airport and the Monroe NLU weather stations reported 16.07 and
20.66 inches of rainfall, respectively. During the flooding of
December 1982 and January 1983, Bayou LaFourche, which served
as an outlet for Chauvin Bayou/Canal L-11 during the high
stages of the Ouachita River, was too high to permit the
Chauvin basin to drain. The
flood stage of Chauvin Bayou reached 71.75 NGVD at US Route
165. This
resulted in President Reagan visiting the area and
subsequently declaring the area a national disaster, which
made possible Federal Disaster Assistance. Flooding occurred in the northern areas of the parish in April and May of 1991. The rainfall that occurred during that storm was near the 100-year flood rainfall. The Ouachita River reached a record level of 81.92 feet NGVD on May 4, 1991. This record crest followed extensive rainfall in the Ouachita River Basin. The flood stage of Chauvin Bayou reached 73.2 feet at US route 165. The lower three miles of the Youngs Bayou floodplain is almost completely devoted to timber growth and the next four to five mile reach is agricultural development with scattered residential development. Business and residential developments in low-lying areas of the Black Bayou floodplain are subject to periodic flooding.
2.2
Recent Disaster History Ouachita Parish has had a number of natural disasters in the past years. Since 1965, there have been nine occasions on which the parish has been declared a disaster area by the President of the United States. Generally, severe storms and flooding have created the disaster situation, however, tornadoes, hurricanes and ice storms have had disastrous effects as well. Ouachita Parish has had many flood occurrences. Though these floods were quite severe in the Parish, they were not severe enough across numerous parishes to warrant a Federal disaster declaration. See Table 2.2 for a detailed account of the Federally declared disaster history of Ouachita Parish. Table 2.2
Presidential Disaster Declarations in Ouachita Parish 1965 to Present
2.3
Flood Disaster A flood is a temporary condition where normally dry land is
inundated by water. Floods
in Ouachita Parish usually come in two various forms: riverine
and sheet flow. Riverine flooding occurs when excessive rainfall from areas upstream of the problem area exerts pressure on rivers or drainage channels. Riverine flooding is usually a gradual process, with warning time from several hours to several days in many cases. River water surface elevations exceed the natural banks of the channel inundating the areas within the floodplain or beyond. Riverine flooding has the tendency to remain in flood stage for a longer period of time than other types of flood hazards. In many cases, riverine flooding may cause greater flood losses due to the length of time structures are inundated, the velocity and depth of the water, and the debris associated with the fast moving water. Sheet flow, or ponding, in
communities in Louisiana is normally caused by excessive
rainfall that exceeds the design capacities of drainage
facilities. Sheet
flow can be associated with flash flooding after a lack of
rain when clay soils are hardened and relatively impermeable.
Sheet flow tends to have activity of high intensity,
but short duration. Topography,
soil types, and other conditions can also affect the severity
of a flash flood. A
typical flash flood lasts minutes to hours and recedes
quickly. Damages
from flash floods can be severe due to the little notification
and preparation time available.
More loss of life has been caused by flash floods than
any other type of flooding.
Vulnerability Ouachita Parish is subject to periodic flooding from rainfall in that parish and runoff from other parishes that drains through the parish. The low-lying areas that follow the Ouachita River and extend eastward to Bayou Lafourche on the Parish border may experience flooding due to the bottlenecking of rivers and streams and slow drainage of precipitation. Ouachita Parish has been affected by flooding of many different intensities and frequencies. The 100-year flood, the baseline flood used for planning purposes, is defined as a flood from a storm that has a 1% chance of meeting or exceeding the proposed water surface elevation in any given year. Table 2.3
Flood Losses in Ouachita Parish
Direct = policies issued directly by the National Flood Insurance Program WYO = policies issued by Write
Your Own (WYO) independent companies
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