HYDRO22023

• Permit No: C1980004
• IBM Index Class Name: Hydrology
• Doc Date: 6/25/2004
• Doc Name: NPDES Permit
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

Central Appalachia WWTF Water Quality Assessment CO-003
standards, many of the aquatic life standazds aze contained in a table at the beginning of each chapter
of the regulations. The standazds in Table A-2 have been assigned to stream segment COLCLC 13b
in accordance with the Classifications and Numeric Standards for Lower Colorado River Basin.
standazds for metals aze generally shown in the regulations as Table Value Standards (TVS), and
these often must be derived from equations that depend on the receiving stream hazdness or species
of fish present. The Classification and Numeric standazds documents for each basin include a
specification for appropriate hazdness values to be used. Specifically, the regulations state that:
Table A-3
TVS-Based Metals Water Quality Standards For CO-0038342
Based on the Table Value standazds Contained in the Colorado Department of Public Health
and Environment Water Quality Control Commission Re lation 37
Calculated Using the Following Value for Hazdness as CaC03: 400 mg/1
~- '~ ~
;Parameter ~'
,, ~ ? ~
~.. , ... n . _~. ~ ~fn',St
e
ua
~ _ ~.f_t r am*~Yater ;
' t
~ tandard ~
3,'.~, .. _ ~~ ~~ ~ a ; ~. ~ ` ~'~'~"~ ,1` , ~ ~ ~ , 6 ~.,
~_~~~, ~~, t ~, ~ ,~~;~~~ ~~~
~~4= .,,,1' ,, , ,~ ,~ ~~ormula Tlsed ~,.,~ .~,

d
i
Di
l
d Acute 19 llg~1 [1.13667-0.041841n(harMess)][e(1.128(ln(hardness)}3.6867)]
Ca
m
um,
sso
ve ChrOIllC 6.2 ug/1 [1.10167-0.041641n(bazdness)][e (0.7852(ln(bazdness))-2.715)]
Trivalent Chromium, Acute 1773 ug/1 e(o.s19(In(l,anmess)}Fz.s736)
Dissolved Chronic 231 ug/1 e(0.819(]n(hardness)}+0.5340)
Hexavalent Chromium, Acute 16 Ug/1 Numeric standazds provided, formula not applicable
D1SSO1Ved ChrOI11C 11 Ug/1 Numeric standardsprovided, fomula not applicable
Di
l
d
C
Acute
50 ug/1
e(osazzpn(hazaness))-1.7406)
ve
opper,
sso Chronic 29 ug/1 e(ossasM(~raness)}1.7az6)

L
d
Di
l
d ACllte 2$1 Ug/1 [1.46203-0.1457121n(hardness)][e (1.273(ln(bazdness)}1.46)]
ea
,
sso
ve ~,'hrO1nC 11 llg/1 [1.46203-0.1457121n(hardness)][e(1.273(]n(hardness)}4.705)]

M Acute 4738 ug/1 a (0.3331(In(hardness)}F6.4676)
anganese
ChTOI11C
261$ llg/1
e(0.333](ln(bardness)}+5.8743)

l
i
l
d Acute 1513 llg/1 a (0.846(In(hardness)}F2.253)
, D
sso
ve
Nicke ChrOIllC 16$ Ug/1 e(0.846(ln(hardness)~0.0554)
Selenium, Dissolved Acute 1$ llg/1 Numeric standards provided, forrtwla no[ applicable

il
Di
l
d Acute 22 Ug/1 %s e (1.72(ln(hardness)}b.52)
ve
ver,
sso
S ChrOT11C 3.5 Ug/1 a (1.72(]n(bardness))-9.06)
d
i
Di
l
Acute
379 ug/I
C (0.8473(In(hardness)}M.8618)
ve
nc,
sso
Z ChrOIllC 3$2 Ug/l e(0.8473(In(hazdness)}W.8699)
The hardness values used in calculating the appropriate metal standard should be based
on the lower 95% confidence limit of the mean hazdness value at the periodic low flow
criteria as determined from a regression analysis of site-specific data. Where
insufficient site-specific data exists to define the mean hazdness value at the periodic
Appendix A Page 4 of 9 Draft