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An Evaluation of Nitrate, fDOM, and Turbidity Sensors in New Hampshire Streams
Author(s) -
Snyder Lisle,
Potter Jody D.,
McDowell William H.
Publication year - 2018
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr020678
Subject(s) - turbidity , dissolved organic carbon , nitrate , environmental science , streams , particulates , water quality , hydrology (agriculture) , organic matter , total organic carbon , environmental chemistry , chemistry , geology , ecology , organic chemistry , computer network , oceanography , geotechnical engineering , computer science , biology
A state‐of‐the‐art network of water quality sensors was established in 2012 to gather year‐round high temporal frequency hydrochemical data in streams and rivers throughout the state of New Hampshire. This spatially extensive network includes eight headwater stream and two main stem river monitoring sites, spanning a variety of stream orders and land uses. Here we evaluate the performance of nitrate, fluorescent dissolved organic matter (fDOM), and turbidity sensors included in the sensor network. Nitrate sensors were first evaluated in the laboratory for interference by different forms of dissolved organic carbon (DOC), and then for accuracy in the field across a range of hydrochemical conditions. Turbidity sensors were assessed for their effectiveness as a proxy for concentrations of total suspended solids (TSS) and total particulate C and N, and fDOM as a proxy for concentrations of dissolved organic matter. Overall sensor platform performance was also examined by estimating percentage of data loss due to sensor failures or related malfunctions. Although laboratory sensor trials show that DOC can affect optical nitrate measurements, our validations with grab samples showed that the optical nitrate sensors provide a reliable measurement of NO 3 concentrations across a wide range of conditions. Results showed that fDOM is a good proxy for DOC concentration ( r 2 = 0.82) but is a less effective proxy for dissolved organic nitrogen ( r 2 = 0.41). Turbidity measurements from sensors correlated well with TSS ( r 2 = 0.78), PC ( r 2 = 0.53), and PN ( r 2 = 0.51).