About the District
Drainage Districts are special purpose districts created by the Texas Legislature in 1905 serving as political subdivisions of the State of Texas. On January 10, 1919, an election was held in Jefferson County to determine the formation of Drainage District No. 6 and also to determine if bonds could be issued for making drainage improvements to said District, as well as taxes levied to pay for such bonds. On January 21, 1920, Drainage District No. 6 was established after the Commissioner’s Court met in a special session and found that the election was duly and lawfully held and that 84% of the votes cast were in favor of the creation of the District. Drainage District No. 6 is governed by a 5-member board in accordance with statutory legislation who are appointed by the Jefferson County Commissioners Court. This 5-member board has elected to hire a General Manager to oversee all operations for the District.
The District’s jurisdictional boundaries are set in the Northern area of Jefferson County and include Beaumont, Bevil Oaks, China, and Nome as well as the communities of Fannett, Northwest Forest, Hillebrandt Acres, Cheek, and LaBelle and all the farm and timberland in between. Within this area, there are over 1070 linear miles of streams, channels, and outfalls, along with 38 detention basin facilities all under the jurisdiction and control of the District. The other boundaries in which we operate – those provided by nature – are of the 5 primary watersheds within Drainage District No. 6 and each presents unique challenges. All incorporated and unincorporated areas rely heavily on the District to provide outfall drainage and flood relief.
Since its creation, the role of Drainage District No. 6 has become increasingly complex. In 1961, the District was enlarged under Section 59, Article XVI of the Texas Constitution in House Bill No. 1063, which also created and established said enlarged District as a Conservation and Reclamation District. As a Conservation and Reclamation District, the jurisdictional authority was expanded to include, among other things, eminent domain. The Texas Legislature ruled that the powers granted under House Bill No. 1063 were an urgent necessity for effective drainage throughout the District. It was further detailed that the creation of the Conservation and Reclamation District would result in the conservation of the natural resources of the state and eliminate health and safety hazards.
Accordingly, the continuing mission of Jefferson County Drainage District No. 6 is to:
Provide flood damage reduction projects that work, with appropriate regard for community and natural values.
The District accomplishes its mission by:
- Devising Hazard Mitigation Plans
- Implementing the Plans
- Maintaining the Infrastructure
Glossary
A
Acre-Feet
Used to express volume of storage usually in a detention basin. One Acre-Foot is equal to one acre times a one-foot depth or 43,560 cubic feet (325,850 gallons).
Alternatives
Combinations of one or more components that provide a complete plan to reduce flood damages. A number of alternatives may be formulated, and the preferred one is deemed the “recommended alternative.”
Appraisal
A written estimate of the value of an asset or property prepared by a qualified, independent party.
B
Base Flood
A flood having a 1% chance of being equaled or exceeded in any given year. This flood is sometimes called the 1% or 100-year flood.
Base Flood Elevation (BFE)
This is the elevation above the average sea level that waters from a 1% (100-year) flood will reach at a given point along a creek or bayou. These elevations are determined using hydrology and hydraulic computer models. The elevations are then mapped on the topographic data for the county to produce the 1% (100-year) floodplain.
Benefit-To-Cost Ratio
Represents the overall efficiency of a plan. Determined by dividing the value of the annual benefit by the annual cost.
BMP
Best Management Practices
Bridge Modification
The replacement, extension or reinforcement of a bridge in order to remove an impediment to flow or accommodate a channel enlargement.
Buyout
The elimination of potential flood damages to houses or other types of structures by acquiring them and removing them.
Bypass Channel
The construction of a new channel in order to convey stormwater runoff around an area. Usually required due to right-of-way considerations or to avoid environmentally sensitive areas.
C
Capacity
The measure of water capable of flowing through a channel, measured in cubic feet per second (CFS). Also the measure of how much water a stormwater detention facility holds, usually measured in acre-feet (AC-FT).
Capital Improvement Program
The District’s CIP shows the schedule and projected funding for flood damage reduction projects for current and future years. The District’s CIP is presented for a five-year time frame and adjusted annually.
Cellular Concrete Mats
A mat consisting of interlocking concrete “jigsaw puzzle-looking” blocks that is sometimes placed as a lining on the sides and bottom of a channel. These mats increase the efficiency of the flow of stormwater in the channel. Because the blocks have openings through them, grass and other vegetation can grow through them minimizing the occurrence of erosion in an aesthetically pleasing manner.
Channel
A course or passage through which stormwater may move or be directed. It is a generic term used by the District in reference to ditches, bayous, creeks or other smaller tributaries. A channel can vary in shape and size, and can be either natural or man-made.
Channel Flow
The amount of stormwater flowing through a channel, often measured in cubic feet (of stormwater) per second (or CFS).
Channel Modification
A man-made change to a channel’s characteristics, typically for the purposes of reducing flood damages by increasing its overall conveyance. This can be accomplished by widening and/or deepening the channel, reducing the friction by removing woody vegetation or by lining the channel with various materials.
CLOMR
A Conditional Letter of Map Revision (CLOMR) is FEMA’s comment on a proposed project that would affect the hydrologic and/or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway or effective Base Flood Elevations. There is no appeal period. The letter becomes effective on the date sent. This letter does not revise an effective National Flood Insurance Program map, it indicates whether a proposed project would produce a change in a Special Flood Hazard Area by FEMA if later submitted as a request for a Letter of Map Revision.
Closing
The final phase of a transaction, especially the meeting at which procedures are carried out in the execution of a contract for the sale of real estate.
Closing Costs
Fees a home buyer or seller pays at closing, such as property insurance, taxes, attorneys’ fees, an origination fee, an amount placed in escrow, title insurance, mortgage insurance premium, points and filing fees associated with the sale of property.
Compartment
A section of a detention basin designed so that the excavation can be constructed separately, and potentially operated separately, from other sections of the same detention basin.
Components
Specific applications of flood damage reduction “tools,” such as a detention basin or channel enlargement, at a particular location.
Condemnation
The legal process for the taking of private property.
Confluence
The intersection of two or more streams, or where one flows into another.
Conveyance
The ability of a channel or other drainage element to move stormwater.
Corps
U.S. Army Corps of Engineers, also USACE. The federal agency authorized to partner with local governments (such as the District) to conduct major water resources projects. The Corps operates nationally and evaluates funding requirement for all projects. The Corps also supports U.S. military operations. For more info on this region’s Corps, go to the U.S. Army Corps of Engineers, Galveston District’s website at www.swg.usace.army.mil. For more general info on the Corps, go to www.usace.army.mil/.
D/S
Downstream
Deed
A legal document that evidences a person’s ownership of and right to possess a property.
Desired Capacity
A measure of what area communities, in conjunction with the Jefferson County Drainage District No. 6, determine is needed for a project to provide an acceptable level of flood damage reduction. This desired capacity is based on factors such as the extent of flooding, available land and available funding, sometimes through partnerships. See Capacity.
Detention Basin
An area of land, usually adjacent to a channel, that is designed to receive and hold above-normal stormwater volumes. Most stormwater detention basins in Jefferson County are excavated. The detained stormwater then slowly drains over time out of the detention basin as the flow in the channel and associated water surface elevations recede. (also Stormwater Detention)
Disaster Area
When a disaster is beyond the capabilities of state and local government to respond, the Governor must make a formal request to the President to declare the affected region a “disaster area.” When the presidential declaration is enacted, federal assistance is made available to public and certain non-profit entities, as well as to individuals who were adversely affected by the disaster. The assistance is available in many forms, including monetary, temporary housing, crisis counseling and even legal assistance. For more on the Disaster Declaration process, go to: www.fema.gov/rebuild/recover/dec_guide.shtm.
Discrete Segment
Unique term developed to describe the logical pieces of large, long range projects for determining Federal reimbursement to the local sponsor. Once a discrete segment of a project (e.g. defined element of channel or stormwater detention construction) is complete and functional, it qualifies for reimbursement.
Duplication Of Benefits
A situation in which benefits are derived from two federal government-sponsored programs for the same item. An example would be a homeowner collecting flood insurance to cover damage to the home, and then being paid full pre-flood value for the home without deducting the insurance proceeds. The District policy and FEMA regulations prohibit duplication of benefits in a home buyout.
E
Easement
A limited interest in real property for a specific purpose, usually designated in the granting instrument or plat. Another entity or individual has fee title to the property.
Element
A major subdivision of an overall flood damage reduction plan divided based on scheduling, financial or geographic criteria.
Elevation
The vertical distance measured from a datum to a specific point of interest.
Elevation Certificate
An Elevation Certificate is a detailed survey of a structure’s elevation to see if it is above or below the base flood elevation. An Elevation Certificate can be used to reduce the cost of flood insurance or even remove a particular structure from the 1% (100-year) floodplain.
Encroachment
Construction, such as a wall, fence, building, etc., on the property of another.
EPA
Environmental Protection Agency
Escrow
An account established by a lender in which a homebuyer’s funds are deposited for the payment of items such as property taxes and homeowner’s insurance.
Existing Capacity
The measure of how much water a channel can currently carry, measured in cubic feet (of stormwater) per second (CFS). Also the measure of how much water a stormwater detention facility can currently hold, usually measured in acre-feet (AC-FT) of volume.
F
Fair Market Value
“The most probable price which a property should bring in a competitive and open market under all conditions requisite to a fair sale, the buyer and seller each acting prudently and knowledgeably, and assuming the price is not affected by undue stimulus…” The value for District transactions is determined by an appraiser, licensed or certified by the State of Texas.
Fee Simple
Full ownership of real property by an individual or entity.
FEMA
(Federal Emergency Management Agency) – The federal agency responsible for providing leadership and support to reduce loss of life and property and to protect our institutions from all types of hazards. This is accomplished through a comprehensive, risk based, all hazards emergency management program consisting of mitigation, preparedness, response, and recovery. In relation to flooding hazards, FEMA is the federal agency responsible for administering the National Flood Insurance Program (NFIP).
FIRM Panel
FIRM stands for Flood Insurance Rate Map. In order to print the FEMA Flood Insurance Rate Maps at a scale of 1-inch = 1,000-feet, the maps are broken out into over 150 FIRM panels that cover the entire Harris County area.
Flap Gate
A flap gate is a simple mechanical device used to control the direction of flow of stormwater and is typically used at the end of a pipe draining into a channel. The flap gate allows water to drain from the pipe into the channel but closes when stormwater in the channel begins to rise higher than the water being delivered by the pipe.
Flood Bench
Typically, a design feature obtained by enlarging a channel’s cross-sectional geometry so that it varies in width and steepness, creating flatter slopes and even plateaus, giving completed segments more of a natural appearance.
Flood Insurance Rate Maps
Prepared by FEMA, Flood Insurance Rate Maps, or FIRMs, show areas that have the highest probability of flooding and illustrate the extent of flood hazards in a flood-prone community. These maps are used to determine flood insurance rates for communities participating in the National Flood Insurance Program (NFIP).
Properties located in mapped zones AE, AO, A, or VE are required to have flood insurance if the owner has a federally backed mortgage on the property.
Flood Insurance Study
A study FEMA initiates to undertake a new hydraulic and/or hydrologic analysis for streams within a community. Often, these studies incorporate the new information into the FEMA Flood Insurance Rate Maps (FIRMs).
Floodplain
From time to time, bayous and creeks naturally come out of their banks due to heavy rainfall and inundate the adjacent land. This area that is inundated is referred to as a floodplain. Residences and businesses within the floodplain are considered to be at risk of being damaged by flooding. The floodplain is typically expressed by stating its frequency of occurrence. For example, the 1% (100-year) floodplain represents an area of inundation having a 1% chance of being equaled or exceeded in any given year, whereas the 2% (50-year) flood plain has a 2% chance of being equaled or exceeded in any given year. FEMA Flood Insurance Rate Maps (FIRMs) show the 1% (100-year) and 0.2% (500-year) floodplains.
Floodway
For most waterways, the floodway is where the water is likely to be deepest and fastest. It is the area of the floodplain that should be reserved (kept free of obstructions) to allow floodwaters to move downstream. Technically, the floodway is typically calculated by finding the area that must be reserved to carry and discharge the 1% (100-year) flood without increasing the base flood by more than 1-foot.
Flowline
A line formed representing the lowest point in the bottom of and along a specified length of a channel.
Fluvial Geomorphology
The study of river behavior and river-related landforms, such as riverbeds, floodplains and stream forms.
FY
Fiscal year
Gabion
Rock-filled wire baskets either laid as mattresses or stacked in a manner that forms a retaining wall. Gabions are sometimes used to support the banks and sides of channels for structural reasons, as well as minimize the occurrence of erosion.
GIS
(Geographic Information System) – A computer program or programs used to store a wide variety of types of information and link that information to a specific geographic location. Some examples of this information the District utilizes would be streets, bayous and channels, HCAD parcel data, contours, floodplains and all the data that supports this information such as names, location and much more.
GPS
(Global Positioning System) – GPS is a system that uses satellites to accurately determine the location of any point on earth, and it helps to create the most accurate floodplain maps possible.
GRR
General Re-evaluation Report. Submitted to USACE for approval of a revised plan for all or part of a project.
H
Hydraulics
The study of moving fluid. In the case of the District’s work, hydraulics refers to analyzing the movement of stormwater flows in channels, pipes and detention basins to determine certain properties like stormwater depths and stormwater velocities.
Hydrology
The study of the rainfall-stormwater runoff process. Hydrological procedures are used to estimate the expected amount of stormwater entering a drainage system from a certain amount of rain falling over a certain watershed area.
I
Impacts
The expected change in stormwater characteristics (i.e. stormwater flow), velocities and depths caused by proposed changes in the watershed.
Infrastructure
The land, buildings and other assorted structures that serve public use. Infrastructure typically refers to the primary drainage system, including channels and detention basins (not streets, storm sewers, and roadside ditches).
Insufficient Capacity
Exists when the desired capacity of a channel or stormwater detention facility exceeds the existing capacity; that is, when a channel or a detention facility cannot carry or hold all of the stormwater that could flow to it.
No terms for “J – K”
Levee
A physical barrier constructed to protect areas from rising floodwaters.
LiDAR
(Light Detection and Ranging) – LiDAR is a commercial technology that uses a laser mounted in an airplane to measure the elevation of the ground.
Lien
A legal claim allowed to a creditor against a debtor’s property that must be paid when the property is sold in order to transfer.
LOMR
(Letter of Map Revision) – FEMA’s modification to an effective Flood Insurance Rate Map (FIRM), or Flood Boundary and Floodway Map (FBFM), or both. LOMRs are generally based on the implementation of physical measures that affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway, the effective Base Flood Elevations (BFEs), or the Special Flood Hazard Area (SFHA). The LOMR officially revises the Flood Insurance Rate Map (FIRM) or Flood Boundary and Floodway Map (FBFM), and sometimes the Flood Insurance Study (FIS) report, and when appropriate, includes a description of the modifications. The LOMR is generally accompanied by an annotated copy of the affected portions of the FIRM, FBFM, or FIS report. An Appeal/Protest period exists only when there is a change in the BFE.
M
Mitigation
To offset the impact of one action by implementing another. Examples of various forms of mitigation, as used by the Jefferson County Drainage District No. 6, include:
- Offsetting the impacts of land development projects. This is usually in the form of a stormwater detention basin. The development area will drain into the stormwater detention basin, and ultimately, into a channel.
- Offsetting the impacts of wetlands/habitat losses. State and Federal laws protect certain wetlands and habitat. Through a permit process, agencies require projects to “avoid, minimize and mitigate” any unavoidable losses. Mitigation is typically done through the recreation of the affected wetlands or habitat areas. Certain wetlands losses can be mitigated with the District’s wetlands mitigation banking.
An individual homeowner can also mitigate financial losses caused by flood damage by purchasing a flood insurance policy.
Mortgage
A legal document that pledges a property to a lender as security for the payment of a loan or debt.
Moving Costs
Expenditures associated with moving, including packing and unpacking, temporary storage of personal property, transportation, moving insurance, disconnecting and reconnecting household appliances and other related items.
Moving Expenses
The direct costs associated with moving the personal property of qualified homeowners from a flooded home that was purchased by the District. (Note that this does not apply for the voluntary buyout program.)
MS4
Municipal Separate Storm Sewer Permit
Multi-Use
The ability to provide more than one use. This usually is in reference to drainage facilities or detention basins that not only provide for flood damage reduction, but can also accommodate other uses, such as hike-and-bike trails, sports fields, wildlife habitat, etc.
N
NFIP
(National Flood Insurance Program) – Created by Congress in 1968 to provide low cost flood insurance for property owners in flood-prone communities. In exchange for flood insurance eligibility, communities agree to implement and enforce floodplain management measures to reduce the possibilities of future damage. FEMA arranges for periodic community assistance visits with local officials to provide technical assistance regarding complying with NFIP floodplain management requirements. FEMA works with local officials to evaluate the FIRMs and associated Flood Insurance Study and conducts updates as needs and priorities dictate.
NOAA
National Oceanic and Atmospheric Administration
Non-Point Sources
Indirect sources of stormwater runoff – such as roadways, yards, or agricultural areas – can be the origins of stormwater pollution in the overall drainage infrastructure.
NPDES
(National Pollutant Discharge Elimination System) – As authorized in 1990 by the Clean Water Act, NPDES is a federally mandated permit program intended to control water pollution by regulating point sources that discharge pollutants into waters of the United States. Under the storm water component of the permit program, the federal government requires municipal separate storm sewer systems (MS4s) serving a population of 100,000 or more to have a stormwater NPDES permit.
O
O&M
Operation and Maintenance
Other Frequency Floods
There is an infinite number of frequency floods that can occur. The 1% (100-year) flood is used by many as a standard for regulations, designs, and National Flood Insurance Program purposes. Other floods often used consist of the 0.2% (500-year) flood, the 2% (50-year) flood, the 10% (10- year) flood, and the 50% (2-year) flood.
Outfall
An outfall is simply the pipe, channel, or opening where water “falls out” and then into another body of water, typically a drainage channel. In a typical stormwater detention basin, the outfall is at or connected to the lowest point of the basin so that detained water drains completely.
Out-Of-Bank
The condition in which the water level of a channel rises above the top of its banks and spills into the surrounding land area.
Oxbow
Generally, a U-shaped bend or meander in a channel. Oxbows are sometimes “cut off” and abandoned when a channel is straightened. This can occur both naturally or by man-made means.
P
Pay-As-You-Go
Pay-As-You-Go refers to using current income (cash) instead of relying on debt (e.g. bonds) as a way to fund projects. Cash funding avoids long-term debt and its associated interest payments.
Peak Flow
(or Channel Peak Flow) – The maximum flow of stormwater flowing through a channel at a given location, based on a certain amount of rainfall falling in that area.
Physical Condition
A detailed listing of all of the physical aspects of a channel that can influence its effectiveness. The physical condition includes the bottom and sides of a channel, as well as the condition of structures, such as bridges.
Point Sources
Specific conveyances, such as pipes or man-made ditches that flow into, or are part of the overall drainage infrastructure.
Ponding
The process, occurring after a rainfall when water gathers in low-lying areas throughout a watershed. Frequently referring to water standing in the streets when the capacity of the storm sewer is exceeded.
Project Process
Project Process includes the Feasibility Stage, Development Stage, Property Acquisition and Utility Relocation Stage, Design Stage, and Construction Stage. A funding allotment must be secured for each stage of the project process.
Q
No terms for “Q”
R
Repetitive Loss Property
Homes that have received more than $1,000 of flood-insured damage two or more times in the last ten years will appear on the National Flood Insurance Program (NFIP) repetitive loss database and receive higher priority for certain types of buyouts.
Residences
Any dwellings in which people live, including single-family houses, apartment units, mobile homes, and travel trailers • Right of Way (also right-of-way, ROW) An interest in real property, either in fee or easement.
Right-Of-Way
Land used by a public agency for public purposes, such as building roads or improving channels.
Riparian
(Corridor or Zone) – The area of land along and adjacent to a waterway (river, bayou, creek, stream, etc.). Trees, plants, and grasses along these waterways are called riparian vegetation. A riparian zone from an ecological perspective may occur in many forms including grassland, woodland, wetland, or even non-vegetative. Riparian zones may be natural or engineered for soil stabilization or restoration. In some regions the terms riparian woodland, riparian forest, riparian buffer, or riparian corridor are used to characterize a riparian zone.
Riprap
Rocks or broken pieces of concrete often placed in areas where the flow of stormwater is expected to cause erosion. The riprap serves as “armor” for areas of channels and detention basins to minimize the occurrence of erosion.
Riverine Flooding
Flooding is the result of creeks and bayous leaving their banks as a result of heavy rainfall. This type of flooding is mapped on the Flood Insurance Rate Maps.
Runoff
The stormwater from rainfall not absorbed by the ground that flows into the local drainage system, and ultimately, streams and bayous.
S
SFHA
(Special Flood Hazard Area) – An area defined on a FEMA Flood Insurance Rate Map with an associated risk of flooding.
Sheet Flow
(Overland Flow Flooding) – Flooding that occurs when intense local rainfall flows overland to reach a channel. Frequently, these conditions exist when runoff exceeds storm sewer or roadside ditch capacity, and the water can “pond” in the streets deep enough to flood residences that are not even near a creek or bayou. The water will seek a path to the channel by flowing overland (Sheet Flow). When residences and other structures are in that path, flooding occurs and this type of flooding is not identified on the Flood Insurance Rate Maps.
Stormwater Detention Basins
An area of land, usually adjacent to a channel, that is designed to receive and hold above-normal stormwater volumes. Most stormwater detention basins in Jefferson County are excavated. The detained stormwater then slowly drains, over time, out of the detention basin as the flow in the channel and associated water surface elevations recede.
Substantially Damaged Property
Flood damage to a structure where the cost to repair equals or exceeds 50% of the value of the structure, excluding the land value.
Subwatershed
(also Tributary watershed) – The land area that drains to one of the smaller streams that flow to the main channel of a watershed.
SWMP
Stormwater Management Program
SWPPP
Storm Water Pollution Prevention Plan
T
Topographic Data
Detailed information about the shape of the earth including ground elevations and ground contours.
TPDES
The state program for issuing, amending, terminating, monitoring, and enforcing permits, and imposing and enforcing pretreatment requirements, under the Clean Water Act §§ 307, 402, 318 and 405, Texas Water Code, and Texas Administrative Code regulations.
TPWD
Texas Parks and Wildlife Department
Tributary
A channel through which water may move or be directed that ultimately flows into a larger channel, usually bayous and creeks.
Tributary Watershed
(also Subwatershed) – The land area that drains to one of the smaller streams that flow to the main channel of a watershed.
TxDOT
Texas Department of Transportation
U
U/S
Upstream
Unincorporated Jefferson County
The area in Jefferson County, Texas, not within an incorporated area of a city, town, or village.
USACE
(United States Army Corps of Engineers) – The federal agency authorized to partner with local governments (such as the District) to conduct major water resources projects. The Corps operates nationally and evaluates funding requirements for all projects. The Corps also supports U.S. military operations. The Corps office for this region is located in Galveston, Texas.
No terms for “V”
Wastewater Treatment Facility
An arrangement of devices and structures, excluding septic tanks, constructed and installed for the purpose of treatment of wastewater from domestic, commercial, or industrial sources or combinations thereof, and which discharge its treated effluent into any surface water.
Water Surface Elevation
The distance the water surface in a creek or bayou is above mean sea level, measured at a given location along a creek or bayou.
Water Surface Elevation Profile
Shows the elevation above mean sea level of the 1% (100-year) or 0.2% (500-year) floodplain along all the studied stream miles in a particular watershed.
Watershed
A geographical region of land or “drainage area” that drains to a common channel or outlet, mostly creeks and bayous in Jefferson County. Drainage of the land can occur directly into a bayou or creek or through a series of systems that may include storm sewers, roadside ditches, and/or tributary channels.
Weir
A structure typically constructed to control the timing and amount of stormwater flowing into an adjacent detention basin. As the stormwater level in the channel increases, water flows into the basin over the weir. The lower a weir, the sooner the rising stormwater enters the basin. The longer a weir, the greater the flow of stormwater entering the basin.
No terms for “X-Y-Z”
Benefits of Flood Damage Reduction
Benefits of flood damage reduction:
Tax dollars invested in flood damage reduction, along with other projects by the Jefferson County Drainage District No. 6, have a profound impact on the quality of life in the nation’s twentieth-largest county.
Benefits include:
- Avoided Damages: Construction of flood damage reduction projects and home buyouts means a reduced risk of flooding for residents within the District.
- Trails and Greenspace: When not needed for drainage or stormwater detention purposes, some Drainage District No. 6 properties can do double-duty as recreation areas and provide space for trails across the District.