SPECIAL FLOOD HAZARD INFORMATION
BUFFALO BAYOU SHEPHERD DRIVE 'ID BARKER DAM HOUS'IDN, TEXAS
PREPARED FOR HARRIS SOIL AND WATER CONSERVATION DISTRICT HOUS'IDN, TEXAS
BY
U. S. ARMY ENGINEER DISTRICT CORPS OF ENGINEERS GALVESTON, TEXAS
JUNE 1972
Ji : 1: ·jc.- . Lf13 ,C.3~ lq'll.n-, SPECIAL FLOOD HAZARD INFORMATION
BUFFALO BAYOU SHEPHERD DRIVE 'ID BARKER DAM HOUS'IDN, TEXAS
Introduction Of concern in this report is the flood potential on upper Buffalo Bayou in the reach from Shepherd Drive to Addicks and Barker Dams, a stream length of approximately 24 miles. The report was pre pared in response to requests by the Harris Soil and Water Conservation District, Houston, and the Texas Water Development Board, Austin, under provisions of Section 206, Public Law 86-645 (Flood Control Act of 1960). The report describes and delineates the areas subject to inundation by floods of various magnitudes and frequencies on the main stem of Buffalo Bayou, based upon watershed conditions existing in 1971. Not included are the flood prone areas on tributaries and those that may exist in other areas because of deficiencies in local drainage facilities.
Stream and Watershed Characteristics Buffalo Bayou watershed lies largely within Harris County with small areas in Fort Bend and Waller Counties. The bayou, originating in southeast Waller County at an elevation of about 160 feet above mean sea level, flows in a meandering easterly course through gently sloping grasslands and wooded terrain and thence flows through metropolitan
. ! Houston to its confluence with San Jacinto River and sea level in upper ! Galveston Bay. Of concern in this report is the flood prone land adja cent to Buffalo Bayou in the reach between Shepherd Drive and the Addicks and Barker detention reservoirs. Except for approximately seven miles of rectified channel innnediately downstream from Addicks and Barker Darns, Buffalo Bayou remains essentially in its natural state as far downstream as Shepherd Drive. In this seventeen mile reach, the natural bayou is characterized by a narrow, deeply entrenched channel with steep banks
I!' winding through the woodlands with dense undergrowth in the channel and overbank areas. 1he natural channel does not have adequate capacity within its banks to contain the rainfall r unoff from severe rainstorms occurring over the uncontrolled watershed below the reservoirs and over bank flooding results.
Flood Season and Flood Characteristics 1he Buffalo Bayou watershed is subject to intense local thunderstorms of short duration and general rainstorms extending over periods of several days. National Weather Service records show that the most severe rainfalls and attendant flooding usually occur in the months of February through May; however, flood producing storms can occur any time in the year and particularly during May through October when tropi cal disturbances and hurricanes cause torrential rainfall in the Gulf Coast area.
Streamflow Records and Hydrologic Data Two streamflow recording ga ges, one at the Shepherd Drive bridge and one at the Dairy-Ashford Road bridge, have provided a continu ous record of water stage data since June 1936 and May 1948, respectively. 1he largest flood of modern times on Buffalo Bayou occurred during the period of 6-8 December 1935. This flood resulted from a rain storm centered over the upper part of the watershed near Katy, Texas, where the rainfall totaled 20.8 inches with sixteen inches being recorded in a 24-hour period. Over the Houston area this same storm produced only six to ten inches of rainfall. Other large rainstorms along the Texas Coast occurring within 24-hour periods during the past twenty years are:
Date Location Amount
July 1943 Port Arthur 17.8 inches August 1945 Anahuac 15.9 inches June 1960 Port Lavaca 20.6 inches with 30.9 inches over a 3 day period September 1963 Deweyville 20.6 inches September 1967 Lyford 23.0 inches October 1970 Deweyville 20.7 inches
2 From hydrological or meteorological standpoints, it is reasonable to expect that any or all of these rainfalls could have occurred in the Houston area under the proper combination of circumstances.
Authorized Flood Control Projects Following disastrous floods in 1935, the Congress, at the request of concerned local citizens, authorized a flood control project for Buffalo. Bayou and two of its major tributaries, White Oak and Brays Bayous. From comprehensive studies of many alternate plans, there evolved an overall flood control plan for Buffalo Bayou embodying two detention reservoirs, channel straightening and enlargement, and a program for re lease of floodwaters detained in the reservoirs. In concept, the protec tive system would function by detaining flood flows from the upper 300 square miles of the Buffalo Bayou watershed in the two reservoirs, while flows below the reservoirs would be removed through the improved channel of Buffalo Bayou. Specifically, the overall plan contemplated post-flood releases from the two reservoirs of up to 6,000 cubic feet per second to permit rapid emptying of the reservoirs in preparation for receipt of run off from succeeding storms. Under the operation plan, these releases would begin as soon as inflows below the dams had subsided sufficiently to allow such releases without development of damaging stages in the bayou. Of the components planned for the original flood control pro ject, only the Addicks and Barker detention reservoirs with seven miles of channel rectification downstream of the dams and the Brays Bayou channel improvement have been completed. The White Oak Bayou channel improvement has been completed except for a reach of about one mile above its conflu ence with Buffalo Bayou. Channel improvement on the main stem of Buffalo Bayou upstream from Shepherd Drive through the area of concern in this report has not been completed, and no planning is currently in progress toward its accomplishment.
Developments in the Flood Plain The bayou flood plain areas shown on Plates 2, 3, and 4 are rapidly and intensively being developed with the construction of resi dences, apartments~ townhouses, and related commercial developments,
3 street and utility systems. Connnercial developments are the normal con centration in shopping centers of food stores, specialty shops, restau rants, service establishments, and similar small businesses which usually accompany residential development. 1he area is traversed by Interstate Highways 10 and 610, State Highway 6, and numerous city streets and county roads which afford excel lent access to all developments.
Current Flood Situation Flood control on the Buffalo Bayou watershed has been only partially achieved with the completion of Addicks and Barker Dams. As mentioned above, the original design of the protection system contem plated releases of up to 6,000 cubic feet per second. However, because of continuing encroachment upon the flood plain by intensive urban de velopment, and in the absence of improvements to provide the needed chan nel capacity, it has become necessary to severely limit releases from the reservoirs in order to prevent severe damages to developments downstream. Although releases are controlled to minimize damage downstream, it is im portant to know that the occurrence of damaging floods below and independ ently of the dams is not only possible but likely. 1he floods described herein, specifically the Intermediate Regional and Standard Project Floods, are the results of storms that could occur over the uncontrolled portion of the Buffalo Bayou watershed downstream from Addicks and Barker Dams without any flood releases from the two reservoirs. Also, it must be recognized that local flooding can occur in areas contiguous to the bayou. Such flooding can be caused by inadequate drainage systems which impede the flow to the tributaries and the main stream.
Future Floods From available flood data on past floods for the Buffalo Bayou area and other areas along the Texas Gulf Coast, computations were made to arrive at the 50 year, Intermediate Regional (100 year), and Standard Proj ect Flood profiles shown on Plates 5 and 6. 1he approximate areas that would be inundated by the Intermediate Regional and Standard Project Floods,
4 under present watershed and channel conditions, are shown in light and dark blue, respectively, on Plates 2, 3, and 4. Overflow area delinea tions have not been adjusted for land surface subsidence which may have occurred from continuing ground water and mineral withdrawals in some areas of the watershed. Actual flooded area boundaries should be veri fied during planning stages of land development projects in the bayou flood plain. Purther urbanization of the watersheds will cause greater runoff and higher floods and, consequently, water surface profiles and overflow areas will be larger than those associated with present water shed and channel conditions. Even though Houston has escaped extremely heavy rainfalls for about 37 years, floods of Intermediate Regional and even Standard Project Flood magnitude can be expected to occur in the future. Floods of these magnitudes occurring below Addicks and Barker Dams, without releases from the reservoirs, can be expected to produce high velocities in the Buffalo Bayou channel, resulting in severe erosion of the predominantly sandy and sandy clay banks, thereby jeopardizing structures now located in the flood plain.
Intermediate Regional and Standard Project Floods The Intermediate Regional Flood is defined as a flood having an average frequency of occurrence of once'in 100 years, at a designated location, although it may occur in any year and even in successive years. To avoid the possible inference of regularity of occurrence, the 100-year frequency of occurrence can be expressed in terms of percentage. Thus, a flood with a 100-year recurrence interval would have a one percent chance of occurring in any year. The more severe and less frequent Standard Project Flood is defined as the flood that can be expected from the most severe combination of meteorological and hydrological conditions considered reasonably char acteristic of the geographical area in which the drainage basin is located, excluding extremely rare combinations. Floods largE~r than the Standard Project Flood are possible, but the combination of factors necessary to produce such large floods would rarely occur.
5 Water surface elevations for the Standard Project Flood ex cPed those of the Intermediate Regional Flood by an average of four feet i.n the upper reach from Barker Dam downstream to Wes t Belt Drive, and by an average of seven feet in the lower reach f rom West Belt Drive down stream to Shepherd Drive. A SO-Year Flood would average about 1.5 feet lower than the Intermediate Regional Flood.
Hazards of Large Floods The hazards to life and extent of damage caused by any flood depends on the topography of the area flooded, depth and duration of flood ing, velocity of flow, rate of rise, and developments in the flood plain. Property damage from great floods in developed areas can be overwhelming. The entire community suffers when streets, bridges, sewers, and other public utilities are destroyed or otherwise made inoperative. Water flow velocities greater than three feet per second com-. hined with depths of three feet or more are generally considered hazard ous to life as well as property. Water flowing in excess of four feet per second is capable of transportin~ sediment and causing severe erosion of streambanks and fill around bridge abutments. Where velocities drop below two feet per second, debris and silt deposits can build up, extend ing the flood damage and creating adverse health conditions. In many areas along the bayou there is evidence of serious erosion, silt deposits, and debris lodged in undergrowth in the channel. Brush and debris washing downstream during floods often col lect against bridges or within any restricted flow area, reducing the waterway openings and otherwise impeding flood flows. This creates a damming effect and, depending upon the degree of clogging, causes greater backwater depths with increased overbank flooding. Obstructive new de velopment and future land fill in or near the stream's floodway can be a major factor in intensifying the adverse effects described. For study purposes, it has been assumed that limited clogging can be expected and all bridge structures would stand intact. Significant changes in this premise, imposed by conditions prevailing at the time of a future flood, could alter the estimated flood crests and flood limits shown on profiles and flooded area plates.
6 Uses For This Report The following remarks concerning possible uses for flood data presented herein are meant to provide information on the conse quences of building in flood prone areas without regard to structural damage, economic loss to individuals and the corrnnunity, and the trau matic experience of damage to or loss of homes and personal possessions and the possibility of tragic, needless loss of life. Data presented provide general guidance for future land use planning and are not in tended to be all inclusive.
Possible Solutions For purposes of this report, solutions to problems.of flood plain use have been divided into three major categories - regulatory, nonregulatory, and structural - each with special techniques and alter natives to achieve prudent flood plain use. Compromises between the three categories are often necessary to bring about the most feasible and economical solutions.
Regulatory Techniques Regulation of flood plain land use can substantially contrib ute to the reduction of future flood damage and risk while contributing to other important objectives such as improvement: or preservation of en vironmental attributes. (The use here of the term "regulation" is not meant to imply nonuse of all flood plain lands- or any type of inequitable treatment of present or future landowners.) Federal agencies do not have the authority to regulate flood plain development. This authority is assigned to the states (and their political subdivisions) in the tenth amendment of the U.S. Constitution and has never been delegated to the Federal Government. Consequently, local governmental entities, utilizing available state legislation, must assume day to day responsibility for guiding developments in flood prone areas. Principal regulatory devices used at local governmental levels include zoning ordinances (land use ordinances), subdivision regulations, and building codes: Several Texas cities have regulations of these types.
7 CJ) :I: 0 ~ z 0 .,, ;!! 0 DEVELOPMENT ZONE FLOODWAY DEVELOPMENT Oc (Absolute Minimum Area Needed to Convey Flood Flows ..., ZONE of Selected Magnitude) ·- o~ E 0 -' Area of Flood Plain Water Surface Elevation of a Selected ~ ~- that can be Safely (Flood When Confined Within Floodway ~ > .,, Utilized by Raising Limits (Natural Channel Conditions) ~ -< ,... Natural Ground ~ 0 Elevat;oo ~ Qo 0 -xl 0 m .,, -•::::::::::) '. iI~7Hir liiiiiiii>. "------Ll.t ~=:=-==:,:... ,~=... ]~ ... ====~ ... ===~ .... ~~,.,,~ii ...ii:.,.,.,'='='_...... z ,... CD :..:.;;: ~ ..... ::::::~ ::::~~~:~~A Water Surface E1 evat ion of a Selected f: Fi 11 ~~ ~:: := () > ·····::;;:::A Flood Before Encroachment on Flood f :::::::::::::·· oz;g - ······ Plain > () () ;g :I: 0 I ~ CJ) zmCJ't I ...... CJ) _J m ,... () - ...... ~ - - 0 Natural or Modified Stream ...... z Channel LEGEND () 0 z Ll.H - CHANGE IN WATER SURFACE ELEVATION THAT () CAN BE CAUSED BY FILLl~G IN FLOOD PLAIN m AREA WITHOUT COMPENSATING -CHANNEL .,, ENLARGEMENT ...... CJ) Flood plain zoning ordinances may be amendments to existing zoning ordinances and building codes. 1hey may be used to implement broad land use plans and to reduce future flood losses by stipulating the type of development permitted in flood prone areas. Zoning ordi nances can be used to limit flood plain development by establishing floodway encroachment limits. Zoning ordinances should exclude obstruc tions from floodway areas which adversely affect flood heights and or dinance provisions should allocate the flood plain to uses consistent with the degree of the flood threat. 1he floodway and encroachment limit concepts are illustrated in Figure 1 on Page 8. Subdivision control ordinances are effective means of requir ing construction above selected flood levels in floodway fringe develop ment zones, and requiring adequate drainage fa~ilities to convey rainfall runoff to the floodway from development zones. For example, a city may control the subdivision of land within its jurisdiction by requiring a large percentage of the minimum lot area of a subdivision be at a desig nated height above an adopted flood water elevation as a requisite for plat approval. Unlike zoning ordinances, which e:x:tend only to city lim its, cities have some control over subdivision development in areas with in their extraterritorial jurisdiction. In Texas, extraterritorial jurisdictions vary from one-half mile (population of less than 5,000) beyond the city limits to five miles (population over 100,000) beyond the city limits (Article 970a, Vernon's Annotated Texas Civil Statutes). Building codes may be written to set minimum standards for flood proofing of structures and for establishing minimum first floor elevations consistent with potential flood heights.
Nonregulatory Technigues Other methods that can be used to reduce or avoid flood dam age losses include: a. Fee purchase of lands for open space uses. - Recreational and open space planning should be considered to meet increasing needs of the public. Many loan and grant programs are ava~ilable to local govern ments through the Department of Housing and Urban Development (HUD) and
9 other Federal agencies for preserving flood plain lands as green belts, parks and nature trails, playgrounds, picnic areas, and similar recrea tional pursuits. b. Acquisition of flood easements. - Purchase of less than fee interest in flood prone land is another approach to controlling land use. c. Flood proofing by site filling and structural adjust ments. - After establishing optimum floodway widtqs or encroachment lim its, structures can be built in flood plain fringe areas at elevations above selected flood heights. Flood proofing consists of structural ad justments designed or adapted to reduce flood damage to structures and contents. Such adjustments can be undertaken in existing buildings, or they can be readily incorporated into new buildings during the planning and design stages. With the flood hazard information presented in this report, flood proofing decisions can be made; however, it would not be practical to describe herein all methods available for flood proofing. Consultation with professionals who have a working knowledge of struc tures and flood proofing design could assist in developing adequate flood proofing for most types of structures or facilities. d. Flood insurance. - Flood insurance is now available in cities and counties that adopt appropriate flood plain regulations as required by rules of the Federal Insurance Administration of the Depart ment of Housing and Urban Development. Flood insurance does not reduce flooding or flood caused damage, but it does reduce the risk of large economic losses to flood victims who, for various reasons, must continue as residents of flood prone areas. e. Development policies in regard to extending public ser vices. - Flood conscious governmental policies that limit or discourage extension of public roads, utilities, and other services into flood prone areas can play an important role in encouraging prudent flood plain use. Private developments usually depend on the extension of public services. By avoiding the extension of such services into flood prone areas, local governments and private utility companies can encourage the occupancy of safer and less costly flood free areas.
10 f. Warning signs, erected in prominent places that have ex perienced high water levels, may be used to discourage development in flood prone areas. Signs would carry no enforcement provisions but would serve to inform prospective developers and buyers that a flood hazard exists. g. Temporary and permanent evacuation of flood plains are important means of reducing flood damage. Evacuation of people and prop erty from the path of flood waters would be an expedient for temporary ' alleviation of flood damage. Permanent evacuation of developed areas by relocation of occupants and the removal of improvements, would eliminate potential flood damage and would release flood prone areas for more com patible uses.
Structural Techniques Many tyPes of protective works can be constructed for con trolling floods. Channel improvements may be used to remove constrictions and improve flow characteristics to reduce flood stages. Watershed treatment with retardation structures, ponding areas and small dams, can effectively regulate the rate of runoff to tributaries and the main stream. Levees, dikes, and floodwalls can be constructed to confine the stream to a definite course at stages which may be well above the adja cent flood plain. Some of these methods are generally very costly and, therefore, are more often used in areas where development has already I heavily encroached on the flood plain, or where no other course of action is economically feasible, or where present investments with long range plans preclude alternatives.
Interpretation of Data 'Ihe Galveston District, Corps of Engineers, U.S. Army, upon request, will provide interpretation and limited technical assistance in the application of data presented herein. Copies of this report are available from the Harris Soil and Water Conservation District, P. O. Box 4223, Houston, Texas 77014, the Texas Water Development Board, P. O. Box 12386, Capitol Station, Austin, Texas 78711, and the Galveston District, Corps of Engineers, P. O. Box 1229, Galveston, Texas 77550.
11 GLOSSARY OF TERMS
Flood. An overflow of lands, not normally covered by water, that are used or usable by man. Floods have two essential characteristics: the inundation of land is temporary; and the land is adjacent to and inundated by overflow from a river or stream, or an ocean, lake, or other body of standing water. Normally, a "flood" is considered as any temporary rise in streamflow or stage, but not the ponding of surface water, that results in significant adverse effects in the vicinity. Adverse effects may in clude damage from overflow of land areas, temporary backwater effects in storm and sanitary sewers and local drainage channels, creation of un sanitary conditions or other unfavorable situations by deposition of materials in stream channels during flood recessions, rise of ground water coincident with increased streamflow, and other problems.
Flood Crest. 1be maximum stage or elevation reached by the waters of a flood at a given location.
Flood Plain. 1be relatively flat area or lowlands adjoining the channel of a river, stream or watercourse, or ocean, lake, or other body of stand ing water, which has been or may be covered by flood water.
Flood Profile. A graph showing the relationship of water surface eleva tion to location, the latter generally expressed as distance above mouth for a stream of water flowing in an open channel. It is generally drawn to show surface elevation for the crest of a specific flood, but may be prepared for conditions at a given time or stage.
Floodway. 1be minimum area of the flood plain required to convey a flood peak of a selected magnitude. 1bis usually consists of the most hazard ous area of the flood plain where water velocities are significant. Areas on the landward side of a floodway normally convey little flood flow, although they are inundated during floods.
12 Intermediate Regional Flood. A flood having an average frequency of occurrence in the order of once in 100 years although the flood may occur in any year. It is based on statistical analyses of streamflow records available for the watershed and analyses of rainfall and run off characteristics in the general region of the watershed.
Standard Project Flood. The flood that may be expected from the most severe combination of meteorological and hydrological conditions con sidered reasonably characteristic of the geographical area in which the drainage basin is located, excluding extremely rare combinations. Peak discharges for these floods are generally about 40% to 60% of the probable maximum floods for the same basins. Such floods, as used by the Corps of Engineers, are intended as practicable expressions of the degree of protection that should be sought in the design of flood con trol works, the failure of which might be disastrous.
o-o-o
13 '- "" "-....\ ...
DEPARTMENT OF THE ARMY L------11093 GALVESTON DISTRICT, CORPS OF ENGINEERS GALVESTON, TEXAS ~ STUDY REACH "'ti r INDEX MAP l> ,.,,~ BUFFALO BAYOU HARRIS COUNTY, TEXAS JUNE 1972 1----ll&ILl--I::: LEGEND :::, OVERFLOW LIMITS M. K. T. R.R. t
NTERMEDIATE STANDARD REGIONAL PROJECT tFLOOD FLOOD
STORMS CENTERED ON WATERSHED BELOW RESERVOIRS • All DAM GATES CLOSED
M +20 MILES ABOVE SHEPHERD DRIVE
HOUSTON CITY LIMITS
NOTES I. LIMITS OF OVERFLOW SHOWN MAY VARY FROM ACTUAL LOCATION ON GROUND AS -EXPLAINED IN THE REPORT
2 . AREAS OUTSIDE THE OVERFLOW LIMl;fS SHOWN MA)' BE SUBJECT TO FLOODING FROM RAINFALL RUNOFF Q a: ""'-"~r..-_.._.. 3. FLOODED AREAS SHOWN REFLECT 1971 ..J ..J CHANNEL CONDITIONS AND WATERSHED UJ DEVELOPMENT AS EXPLAINED IN THE REPORT 0 ;it ~~ WESTWAY , N -en 1"700 14300 3 > :w:: c I.> % -> ~ ~ 1"700 BRIARFOREST 2 3 4 13800 BRIAR FOREST 13!500 134'00 13000 PLATE INDEX ~ c( -- 0 ,....8 a: :w:: LU (,) .lll: a: ~ c( ~ al !/) II: UJ a 3= SCALE IN FEET 1000 0 1000 . zooo 6 WESTELLA DR --- ... --- - Ul a..J II: 0 DEPARTMENT OF THE ARMY ..J ) a: i GALVESTON DISTRICT, CORPS OF"ENGINEERS Ci 0 WALNUT GALVESTON, TEXAS BEND
FOREST PARK FLOODED AREAS 0 0 0 xO .,. ..JN { : ON CE~~~~RY ~ BUFFALO BAYOU N II: 13300 F. M. 1093 1280() N : •:-'. F.M . 1093 WESTHEIMER R A 12300 HARRIS COUNTY, TEXAS F. M.1093~ JUNE 197 2 N PL ATE 2 LEGEND 8URICHAllOT RO.
SPRING OVERFLOW LIMITS ::> -' OLD KATY RO D CLUSTER VALLEY ATY·· ROA ~N TE RMEDIATE STANDARD KATY FREEWAY REGIONAL PROJECT :c l _, ...z " z FLOOD FLOOD ....J '-' - a: a: 0 IL 2 "' STORMS CENTERE D ON WATERSHED BELOW RESER VOI RS · ALL DAM GATES CLOS ED a: 0 -M+ 10 MILES ABOVE SHEPHERD 1- DRIVE ...... J m ...... ------...... HOUSTON CITY LIMITS
NOTES
I. LIMITS OF OVERFLOW SHOWN MAY VARY FROM ACTUAL LOCATION ON GROUND AS EXPLA IN ED IN THE REPORT
2. AREAS OUTSIDE THE OVERFLOW L IM I TS SHOWN MAY BE SUBJECT TO FLOODING JACK LA FROM RAINFALL RUNOFF
CARL LA. GREENBAY ~ ~ - --L- 3 FLOODED AREAS SHOWN REFLECT 197 1 u c CHANNEL CONDIT IONS AND WATERS HED 0 FOREST u DEVELOP MENT AS EXPLAI NED IN THE REPORT GLEN M N
2 3 4 ; -I SAR"f.()GA PLATE INDEX I!
...t-- ... u"' J ~ Q:i a: ,!.....=> Oi a Briargrove ; Z ' C z Park SCALE IN FEET
BUFFALO BAYOU WESTHEIMER WESTHEIMER RD HARRIS COUNTY, TEXAS JUNE 1972 VALVERDE PLATE 3 •
t i.LI I.LI u. 30 z z 0 t <( ~ 20 ...J w
10 STREAM BED
0 0 DEPARTMENT OF THE ARMY ~ GALVESTON DISTRICT, CORPS OF ENGINEERS NATURAL CHANNEL GALVESTON, TEXAS
8 7 6 5 4 3 2 FLOOD PROFILES MILES ABOVE SHEPHERD DRIVE BAYOU BUFFALO BAYOU HARRIS COUNTY, TEXAS JUNE 1972 PLATE 5 90r--~------~----~------~------~------..------.------..,------900 >- a: t- t- ~ a: oo wen ...J <( - LL W t <( :r: <( a: LrJ LrJ a: z 0 0 enO U > CD > W 0 a: i-~~.---4- c:r n: ...J er ... a: z w a.. LrJ ,,,.. o en o ~ ~ > 0 • Cl: 'i 80 :::.::: \ I \ w STANDARD w >- <( :::> WO ~ ~ ---! s:;--- -~---- 3: /~ROJECT FLOOD o za:: ~ CD ...J 0 --..;::::::::...... ""==,-==== - ---~4t--___ ----.:..JCL_ ------a.. C1> C\I C1> g~ \ ,-~~~\~/\ 1,--::~i---~---,--- -~ ~ ~ V \ I\ /\ 1 \ / \ t\ I ) ------....170 en ~ 70 (!) ~ 1 w \ I \ I \,' V \ I \ 11 1 ------=:::::::::-::-~ __ ~ (.) 1 (.) u) ~~ \I \I \ ' l ~-- u) ::;j ~~ \I \I \I I ------::;j g- \( I INTERMEDIATE REGIONAL FLOOD . - -...J ...J c:r I 50-YEAR FLOOD en 60 \ - l 60 en ~ t \J \AVERAGE SNKXJA/~:NT ro r\NNEL) (\ t LaJ w LaJ LaJ LL LL , 50 z z 50 \ 1" ...,/'\./ \... J \ I \ I \..._' t \ , I \ I \ I \ ,. z ,1 \ I z 0 \ I .... \ I \ I \ I 0 t <( \ I \ I ~ I 'J ' > > \I \ I \ I 40 w w 40 \ \ ...J ~ , I w ~ \ ~ \ ' \ I, ~ 30 IMPROVED CHANNEL 30
NATURAL CHANNEL 20 20 • DEPARTMENT OF THE ARMY GALVESTON DISTRICT CORPS OF ENGINEERS GALVESTON, TEXAS
2~6______2_5 ______2_4 ______2_3 ______2 __2 ______2_1 ______2_0 ______1__9 ______1_8 ______1_7 ______16______15______14----.!.---~13 10 10 FLOOD PROFILES
BAYOU MILES ABOVE SHEPHERD DRIVE BUFFALO BAYOU HARRIS COUNTY, TEXAS JUNE 1972 PLATE 6 lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll 3 0233 0072756 6 U.S. ARMY CORPS OF ENGINEERS