DR0201-CS020926Carter Burgess
MEMO
TO: Terry Foyt, P.E.
DATE: September 26, 2002
FROM: L. M. Brennan, Jr., R.E.M.
SUBJECT: Maintenance Dredging of Denton Creek PROJECT NO: 992078020
In the Vicinity of MacArthur Blvd., City
O opaell
Dear Mr. Anderson:
Carter & Burgess was requested to sample sediment materials along Denton Creek between
the points identified as N 498141.15 / E 2173205.18 and N 498427.710 / E 2175105.606 to
determine the suitability for the disposal of dredge materials. The proposed dredging will
remove accumulated sediments from Denton Creek in the vicinity of MacArthur Blvd. between
the above points. Historic accumulation of sediments from local development and the
construction of the Denton Creek Flood Control Channel have caused the original creek channel
in this area to become choked and is restricting low flow conditions. The Denton County Levee
Improvement District No. 1 intends to dredge this section of the creek to improve normal low
flow characteristics. Dredge materials will be removed and used as fill material at other
development sites. This sampling was conducted to insure that proposed dredging materials
have not been contaminated by local development activity and that the dredged materials are
suitable for disposal as fill material.
The attached Project Overview Map prepared for this dredging project identifies civil stations
from west to east along the proposed dredging area. Four (4) soil samples were collected from
creek sediments at civil stations 4 +00, 14 +00, 22 +00 and 29 +00. The soil samples were grab
samples from a depth of one to two feet in the creek sediments. These shallow samples were
collected to assess potential impact from surface releases of substances, which may have
occurred during residential development of this area. Each sample was collected in a 16 -ounce
jar, preserved and sent to Certes Environmental Laboratories under a chain of custody protocol.
Samples were analyzed for the following contaminants:
• Priority Pollutant Metals (14 metals)
• Chlorinated Pesticides
• Chlorinated Herbicides
• SVOC's (8270c)
• Phosphate Pesticides
• Total Solids / Volatile Solids
• Total Petroleum Hydrocarbons (TX 1005)
99207802.M01.doc
Analytical results indicated that all organic analyses for herbicides, pesticides, SVOC's and total
petroleum hydrocarbons were below detectable limits. Analysis of inorganic metals indicated
low levels of arsenic, chromium, copper, nickel, lead and zinc. In all cases these levels were
below naturally occurring levels of metals as published in the U. S. Geological Survey (USGS)
Professional Paper 1270 "Element Concentrations in Soils and Other Surficial Materials of the
Conterminous United States" for the Dallas — Fort Worth Metro Area. In summa hebes based tno
ana results, which are provided as an attachment to this letter,
contaminates of concern identified in the representative soils tested from the proposed Denton
Creek Dredging Project. The disposal / reuse of dredging materials recovered from the creek
bed does not appear to pose an environmental concern.
cc: Ms. Terisa Turner — City of Coppell
Correspondence
99207802.M01.doc