Statement of Purpose

1
Fecal Pathogens in Houston Bayous CIVE4312 Hanadi
Rifai
2
Pathogens

• Disease-causing bacteria and viruses associated
  with the presence of fecal matter cause

• Health problems and
• May require stream, beach, and shellfish bed
  closures.

3
Present Standards

• FC Geometric Mean lt 200 cfu/dL
• No more than 10 of all samples gt 400 cfu/dL
• Not less than 5 samples collected over not more
  than 30 days
• Noncontact Recreation x10
• Applicable to most waters

4
Major Reason for Listing is Failure to meet
Contact Recreation Use

• Even with screening levels more restrictive than
  standards
• 60 of 147 segments in 1998
• 80 of 199 segments in 1999
• 110 of 243 segments in draft 2000

5
TNRCC Proposed Contact Recreation Criteria
6
GULF OF MEXICO
7
When are conditions suitable?

• Independent of Bacteria Levels Would I Let My
  Kids Swim Here?

8
Factors to Consider in determining suitability

• Velocity
• Depth
• Clarity
• Temperature
• Others including floating debris and dangerous
  wildlife

9
Water Velocity-2 ft/sec

• World record swimming speeds are in the 5 to 7
  feet/second range. Only a small part of the
  population can sustain 2 feet/second

10
Water Depth-18 inches

• Wading and Swimming are different. EPA Region 6
  has approved use of 18 inches in determining when
  a stream is capable of attaining the swimming
  use.

11
Clarity-Enough to see the bottom or .5 m

• European criteria recommend minimum of 1 m
  visibility. Water with half the clarity should be
  unsuitable for swimming.

12
Temperature-59 F

• Australian guidelines list 15 C (59 F) as a
  lower range for swimming suitability.

13
Other Parameters

• Floating Debris could pose hazard to swimmers
• Alligators and water snakes not conducive to
  swimming safety
• Neither directly related to water quality
  standards

14
Land Use Water

• The way we use our land affects
• water quality and quantity.

USGS
15
Cause And Effect
Increases in the intensity of land use and
urbanization typically result in an
increase in impervious surfaces which lowers
water quality and affects water quantity.
16
Impervious Surfaces
. . . are made up of materials like concrete,
asphalt, roofing, and compacted soil which
prevent percolation of runoff into the ground.
17
Whats The Point?

• Water quality in a river, stream, lake or other
  water body is impacted by both point sources
  and nonpoint sources of pollution.

18
Point Sources of Pollution

• . . . are identifiable sources of pollution such
  as a pipe or ditch from a municipal or industrial
  wastewater treatment facility.

19
Nonpoint Sources of Pollution

• . . . are created when rain, snow or irrigation
  runoff flows over or through the ground and picks
  up

• Anything thrown, dumped, or spilled on the
  ground, or
• Deposited on the ground through air discharges.

NEMO
20
Potential Sources of Pathogens in Bayous
Wastewater effluent not completely disinfected
Untreated sewage from failed on-site WW systems
in un-sewered areas
Regrowth or reactivation of bacteria after
discharge of wastewater
Bacteria from birds concentrated at bridges
Bacteria from storm sewers.
Bacteria from runoff
.
Discharge of untreated sewage due to sewer leaks
or blockage
Bacteria associated with stream sediments
Bacteria from reservoirs
21
Upstream sources
Point Sources
Animals
Runoff
Die-off
Illicit Discharges
Regrowth
Failed Septic Systems
Sediment Resupply
22
Subwatershed Conceptual Model
Wildlife Waste NPS accumulation
Upstream Inflow Load
Scour settling
WWTP and storm water flow and load
Decay in Water and Sediment
WWTP SW discharge
23
Sediment as a Source of Bacteria

• Bacteria concentrations in sediment
• Resupply

24
Houston Bayous

• Watershed and pathogen data

25
Buffalo and Whiteoak Bayous
26
Landuse in Buffalo and Whiteoak Bayous
Open Land
Residential
Commercial
Source HGAC, 2000
Water
27
Rain and flow gage locations
28
Cumulative Flow Frequency Curves for Buffalo
Bayou at West Belt
29
Time Series of Buffalo Bayou FC Data
STN 11360 - WEST BELT, KM 34.6 FLOW lt 100 CFS
400 cfu/dL
30
Time Series of Buffalo Bayou FC Data
STN 11351 SHEPHERD DR, KM 7.0 FLOW lt 100 CFS
400 cfu/dL
31
Historical Water Quality Data
32
Historical Flow Data at Dairy Ashford
33
1992-1999 FC Data along Buffalo Bayou
Geometric means /- standard deviations
0 Km is at boundary of Segment 1013 with Segment
1007
River Km
34
Correlation between Flow and Fecal Coliform
35
EC in BB sediments
36
EC in BB sediments (contd)
37
Cumulative Flow Frequency Curves for Whiteoak
Bayou at Heights Blvd.
38
Time Series of Whiteoak Bayou FC Data
STN 11387 HEIGHTS BLVD, KM 5.2 FLOW lt 50 CFS
400 cfu/dL
39
1992-1999 FC Data along Whiteoak Bayou
Whiteoak
Bayou
Cole Ck
Little
Unnamed
Tributary
Tributaries
Unnamed
Geometric means /- standard deviations
0 Km is at confluence with Buffalo Bayou
40
EC in WO sediments
41
Runoff study WO at Houston
42
EMCs for E. coli (MPN/dL)
Source The Houston Municipal Separate Storm
Sewer System (MS4) Permit
43
DWSS Sampling
EC (MPN/100 mL)
0-394
gt 394