drir.king water supplies drawn from the lower Mississippi River is desc=ibed ~n this paper. Potential sources of contamination of public water supplies re$ultinq ...
RESOURCE DEVELOPMENT OF THE LOWER MISSISSIPPI RIVER MU::RJCAN WATER RESOURCES AsSOCIATION
1991
A GIS APPROACH TO POTABLE WATER PROTECTION ON THE LOWER MISSISSIPPI RIVER
Helen H. Bostock', Paul A. Richards,: Madeline c. Rogers,= and Michael G. Waldon~
~BSTRACT:
~he
application of a qeographic information system \Grs) for
pro~ection
drir.king water supplies drawn from the lower Mississippi River is desc=ibed
~n
of
this
paper. Potential sources of contamination of public water supplies re$ultinq from pollut:ant spills or releases on the Miss.,t..ssippi 1Hver are !.dentified by a GIS dE-vel¢ped specifically fer the Mississippi River Industrial corridor in Louisiana. l'he G!S
includes a relational database, which is gee-referenced through a digiti~ed map of the River. ln add:.tion to loc:at.lon, the database includes information on discharger out.fa.lls and drinking water int.akes. This paper discusses the development of the digi~al graphics model and geo-referenced dacabase, and work in progress that will in~erface the exist.l09 ;rapnics and database with a nume~ical model tha~ estimates the time-cf-travel on ~he River at various flows. Application of the CIS and time-oftravel model programs in surveillance of an actual chemical spill in the River is described. Y~Y
GIS; Mississippi
~ERMS:
Rive~;
Water Quality Monitoring; Time-of-Travel Model,
1 Detection; Early Warning Sygtem.
INTRODOCTION ~he
Gls for the lower
M~ss1ss1pp1
River wa$ designeo
pr~marily
~o
aeaist the
Louisiana Department of Environmental Quality (LOEQ), Office of Water Resources (OWR) in it-s mission to manage and rnaintair. water quality. The project was carried out through an ~nteragency agreement between the OWR and the Center for Louiaiana Inland Wd.l..i:::!l.~,
D~pa.L:.:.;uen!..
o!
~hysical
been
Un.iv~I:"~.i.ty
:::ivil :t:ugJ.nei;:;!'L.i.ny,
of Squt:hwe:~tt::.t.n Lc,~u..i.~i..:\na.
Attributes of the River
Hydrodynamically,
the Mississippi River is unique.
contained by the
levee
Gt~~cture~,
the volume of
system and
~ater,
the
Even though the River has is regulated by the Old River control
meand~rz,
and tho deep
~hAnnel
ere~t~
mixing and
tlow cnaracter~stics which are di!ferent from those found i:. smaller North American river.s. '!'he lower Mississippi River is utilized for multiple~ and o!ten conflicting purposec.
A~
a
drLnk~ng
water Gource for over a million p9ople,
th~
quali~y
of
~h~
water must be maintained. However, the River is also used for the transportat~on of ra·,... materials by cargo ships, and the transportation of finished or intermediate pr::>d'..lct:s by barges Additionally, the River is a source of cooling water for industrial f~cili~iQg,
and a disehargQ modium for
~unicipal
and
irtdust~~al
wastQwat~r.
1
Environrnenta..l Engi:.1eer, C-K Associates, In::., 17170 Perkins Road, Satan Rouge, t.A
70~10.
=Professor and Center Director, Research Associate, and Research Associate Professor, respectively, Uniyersity o~ Southwestern Louisiana, Department of Civil Engineering, Center for Louisiani':'l. Inlatld Wa.t.er
St'\.ld.i.e~"
29
P.O. Dox 42.291, L&.CQyecL\0:1, LA 70504.
The basin drained by the Mississippi River stretch$s as far east as Naw York and Pennsylvania, as ta~ nor~h as Minnesota and as far west as Montana. The area o! foc~s :for discussion in this pa~r represents only one 300 mile segment:. of -..:.he basin. However, flows originating in this enormous upper drainaqe area are literally funneled through this ~ower 300 mile River segment. This 300 mile segment is therefore at riak not only from ~he extensive transportati~n, industrial, and municipal users within the segment, but also from pollutant sources throughout this diverse and expa.nsi ve watershed. Water Quality Management and GIS The
application of
GIS
to
the Lower Mississippi
River
provides
a
spacial
perspective to the narrative and numerical informa~ion needed to adequately manage water quality withir. the 300 mile segment. Beyond the digital rr.apping aspect:., the GIS provides a mechanism for retrieva~ of relevant i~formation through either a graphical user interface, through the applica~ion of more traditional non-graphical database query methods, or sed to lnclude volatile organic chemical sampling. Tne parameter list now includes 22 volatile organlc chemicalst identified by the US EPA, aa priority pollutants. At the pre$ent time, the WQN monitoring sites are in the GlS. :n the future, for assessment purposes, the monitored concentrations for varioQS water quality parameters may be incorporated. The Early Warning organic Compound ~etection System {EWOCDS) was established in 1986. Tha primary rr.iss.l.on cf EWOCOS is to provi.de water providers with a timely r,.,·arn.:...ng of the approach ~o t:heir iz:t.akes of hi9b levels of priority pollutants. This warn~ng should alljw water providers to avoid intake of excessively contaminated river ,..rat:er. ~here
ara Ewocos
mon~toring
locations at both municipal and industrial water
intakes. At first, sampling was carried out on a daily basis. Manual sampling was increased to 2 times per day at most of the s~tea in August, l989. In May, 19901 an ~u~oma~ic
sampler was installed at the
seven -cimes per- dd.y
