Project Name: Infiltration and Exfiltration Study of Selected Areas
Basin: R
Sub-watershed Location: Stream Segment 2304
Sub-watershed Description: The study was conducted just east of I-35 across from
downtown in the neighborhood named El Azteca and surrounding area along the bank
of the Rio Grande River.  The approximate location of the study area is 99* 29'
57"W by 27* 30' 12"N.

Lead Entity: City of Laredo Water Utilities Department
Other Participants:
Funding Source: City Funds
Amount of Funding: $100,000  (specifically for study only)
Project Start Year: 1996
Project Finish Year: 1997

Contact: Fernando Roman, P.E. - Director of Utilities
         Water Utilities Department
         City of Laredo
         P.O. Box 2950
         Laredo, Tx.  78044
         tel: (956) 795-2600
         fax: (956) 795-2605
         e-mail: froman@compuhardt.net

Abstract: The City of Laredo is a historic place which has inherited many old
neighborhoods.  Some of the oldest infrastructure is our sanitary sewer system.
Based on a previously conducted study in the El Azteca, Matamoros and
Musser/Smith areas, the City located defects in the sanitary sewer system which
include broken pipes, cracks and deteriorated manhole structures.  These defects
impact creeks and the river through the processes of infiltration and
exfiltration.  During rain events, th e runoff penetrates the ground and
infiltrates through the defects of the sanitary sewer. This increased discharge
exceeds the capacity for which the system was designed and overflow through
manholes takes place.  This is called exfiltration and the sewage continues it's
untreated journey to the storm sewer, creeks and river.  With the location of
these defects the City will be able to eliminate them as hazards to
environmental quality.

Progress to Date: The studies previously mentioned have been completed and
planning for further investigations continues.  In August of 1997, the EPA sent
notice of additional funding to it's regional offices for grants to be awarded
to public entiti es for projects such as infiltration/exfiltration studies.
These funds are authorized through the Clean Water Act 104(b)(3).  In September
of 1997, the Water Utilities Department of the City of Laredo submitted a grant
proposal to the EPA to receive a parcel of these funds to conduct further
studies.  The following is a list and approximate location of areas to be
studied.

        Baltimore St.           99* 30' 32"W by 27* 31' 56"N
        Riverfront              99* 30' 35"W by 27* 30' 11"N
        Tinaja                  99* 28' 42"W by 27* 28' 42"N
        Lakeside                99* 27' 09"W by 27* 32' 01"N
        McPherson & Gale        99* 28' 45"W by 27* 33' 20"N

The city is currently repairing the defects found by the completed study.
Category: A