INITIAL}} EXCEEDANCES EXCEEDANCES 
OPTION EXCEEDANCES ELIMINAT ED REMAINING 
l.a Existing Program 846 61 785 
l.b. l.a. with waiver 846 61 785 
2.a Existing Program, 
Reduced Scope 846 50 796 
2.b. 2.a. with waiver - 846 50 796 
3.a.- Tech-Based Limits for : 
POTW 846 61 785 
3.b. 3.a. with waiver 846 61 785 
4. Water Quality Limits 
for POTW 846 >61 <785 
Se Local Program for 
Documented Problems 846 ; <61{ >>785 
Pr 
6. Guidance Only 846 0-846 
_} An exceedance is defined to be when a POTW causes at least one water 
quality criteria to be surpassed. POTWs causing more than one criteria 
to be exceeded are still counted only once. 
}} It is assumed that there is no ambient concentration of toxic pollu=- 
tants. If there is an ambient concentration of toxic pollutants, then 
the number of initial exceedences will be higher. For example, if 
other sources of pollution account for 50Z of the aquatic lifewater 
of quality criteria, then the initial exceedences would increase 
from &46 (462%) to 1048 (57Z). See Table 3-1. 
{ Assumed to be limited to the effectiveness of the federal back-up 
357 
TABLE 4-3 
EFFECTIVENESS OF THE OPTIONS IN REDUCING EXCEEDANCES} 
(Based on a total of 1,839 POTWs) 
(Option la). However, the actual effectiveness could be as high 
as for Option 4 depending on the steps taken by the POTWs. 
