Influences of Spatial Scale and Soil Permeability on Relationships Between Land Cover and Baseflow Stream Nutrient Concentrations

• Published in: Environmental management (New York) Vol. 45; no. 2; pp. 336 - 350
• Main Authors: Daniel, F. Bernard, Griffith, Michael B., Troyer, Michael E.
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01-02-2010; Springer Nature B.V
• Subjects: Agriculture; Animals; Aquatic animals; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Base flow; Biota; Catchment scale; Cover crops; Creeks & streams; Crops; Drainage; Drift; Earth and Environmental Science; Ecology; Environment; Environmental Management; Environmental protection; Forestry Management; Geography; Glaciers; Land cover; Linear Models; Mathematical models; Nature Conservation; Neural networks; Nonpoint source pollution; Nutrient concentrations; Nutrients; Ohio; Permeability; R&D; Rain; Regions; Research & development; Rivers - chemistry; Sediments; Soil; Soil (material); Soil permeability; Streams; Variance; Waste Water Technology; Water analysis; Water Management; Water Pollution Control; Water quality; Water sampling; Watershed management; Watersheds; USA, Ohio, Little Miami R; USA, Ohio; Row crop; Soil permeability; Aquatic biotic integrity; Water quality; Non-point source; Nutrients; Spatial scale; Land cover
• ISSN: 0364-152X; 1432-1009
• DOI: 10.1007/s00267-009-9401-x

The Little Miami River (LMR) basin, dominated by agriculture, contains two geologically-distinct regions; a glaciated northern till plain with soils three times more permeable than a southern, pre-Wisconsinan drift plain. The influences of two landscape measures, percent row crop cover (%RCC, computed at three spatial scales), and soil permeability (PERM), on baseflow nutrient concentrations were modeled using linear regressions. Quarterly water samples collected for four years were analyzed for nitrate-N (NN), Kjeldahl-N (KN), total-N (TN), and total-P (TP). In till plain streams (
n
 = 17), NN concentrations were 8.5-times greater than drift plain streams (
n
 = 18), but KN and TP were 20–40% lower at comparable %RCC. These differences resulted in TN/TP molar ratios >80 in till plain streams, but <6 in drift plain streams. For till plain steams regression models based on %RCC accounted for 79% of the variance in NN concentrations but only 27% in drift plain streams. However, regressions on %RCC accounted for 68–75% of the KN and TP concentration variance in the drift plain streams but essentially none in the till plain. Catchment PERM influenced the regional NN/KN ratios which were 10-fold higher in the drift plain streams. For both till and drift streams the catchment scale %RCC gave the best predictions of NN, a water soluble anion, but the smaller spatial scales produced better models for insoluble nutrient species (e.g., KN and TP). Published literature on Ohio streams indicates that these inter-regional differences in nutrient ratios have potential implications for aquatic biota in the receiving streams.