Relationships among nutrients, chloride and biological indices in urban Maryland streams

Morgan, RP; Kline, KM; Cushman, SF

HERO ID

3608255

Reference Type

Journal Article

Year

2007

Language

English

HERO ID 3608255
In Press No
Year 2007
Title Relationships among nutrients, chloride and biological indices in urban Maryland streams
Authors Morgan, RP; Kline, KM; Cushman, SF
Journal Urban Ecosystems
Volume 0
Issue 2
Page Numbers 153-166
Abstract Using a spatially extensive urban database constructed from the Maryland Biological Stream Survey (MBSS), we describe the relationships of nutrients in small-order streams to eight defined categories of percent catchment urbanization, correlations between chloride and conductivity in urban streams, and relationships between nutrients and chloride with two Maryland-specific indices of biotic integrity for benthic macroinvertebrates and fish assemblages. Stream nutrients become elevated with increasing percent catchment urbanization, followed by increases in all four measured nitrogen species and total phosphorus at catchment urbanization levels greater than 10%. There was a strong collinear relationship (r ² = 0.90) between chloride and conductivity (trimeans) across all eight urbanization classes, where Cl (mg/L) = −0.397 + 0.188*conductivity (μS/cm). Critical values for all water quality parameters with the two Maryland biological indices were derived using quantile regression, with significant regressions developed for 11 of 16 water quality parameters and the two biotic indices. For nitrate (NO₃-N), the critical thresholds between fair and poor stream quality for the two Maryland biological indices were 0.83 mg/L (benthic macroinvertebrate assemblages) and 0.86 mg/L (fish assemblages). Increasing stream nutrient and chloride levels, associated with widespread catchment urbanization intensity, now affect many small streams in Maryland, with implications for decreasing water quality in major tributaries and the Chesapeake Bay.
Doi 10.1007/s11252-006-0016-1
Is Certified Translation No
Dupe Override No
Is Public Yes
Language Text English
Keyword Water quality; Urbanization; Creeks & streams
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