The Macroinvertebrate Aggregated Index for Streams (MAIS) uses the presence and relative abundances of certain macroinvertebrates, combined with knowledge of their ability to withstand pollution to come up with a water quality "score" for each site. This MAIS score is used to classify streams on a continuum from Good to Fair to Poor.
Average MAIS scores based on 1-12 years of data taken between 1994-2008 in White Clay Creek.
Sites are in order from best to worst based on MAIS score.
Map of stream reaches designated as impaired (in red) by the PA DEP. Poor, Fair and Good classifications are based on Stream Watch data. Not shown on map is that the WCC watershed in Delaware (mainstem, Middle, Pike, and Mill Creeks) is also considered impaired.
Of the 18 long-term monitored sites, only one (Site 11) was rated as having Good water quality, 9 sites were Fair, and 8 sites were Poor.
All headwater sites (Sites 11, 0, 19) rated higher water quality than downstream locations and all sites on the Lower Mainstem were Poor indicating degraded water quality.
Stream Watch results agreed with the assessment by the states (PA DEP and DNREC): water quality in WCC is impaired.
For a listing of site names see the watershed map.