Size-dependent effects of dams on river ecosystems and implications for dam removal outcomes

Understanding the relationship between a dam’s size and its ecological effects is important for prioritization of river restoration efforts based on dam removal. Although much is known about the effects of large storage dams, this information may not be applicable to small dams, which represent the vast majority of dams being considered for removal. To better understand how dam effects vary with size, we conducted a multidisciplinary study of the downstream effect of dams on a range of ecological characteristics including geomorphology, water chemistry, periphyton, riparian vegetation, benthic macroinvertebrates and fish. We related dam size variables to the downstream-upstream fractional difference in measured ecological characteristics for 16 dams in the mid-Atlantic region ranging from 0.9 to 57 m high, with hydraulic residence times (HRT) ranging from 30 minutes to 1.5 years. For a range of physical attributes, larger dams had larger effects. For example, the water surface width bel..., See methods described in main manuscript submitted for publication., , # Size-dependent effects of dams on river ecosystems, and implications for dam removal outcomes

## Description of the data and file structure

File list (files found within DataS1.zip)

brown_et_al_2024_data.xlsx

brown_et_al_2024_impound_wc.csv

brown_et_al_2024_indep_var_values.csv

brown_et_al_2024_spearman_indep_vars.csv

brown_et_al_2024_depend_var_descriptions.csv

brown_et_al_2024_depend_var_up-down_values_and_fract_diffs.csv

brown_et_al_2024_bray_curtis_similarities.csv

File descriptions

brown_et_al_2024_data.xlsx - Supporting data for Brown et al. 2024. Data files in the tabs in the Excel file are also provided as .csv files and are described below. Blank cells in all data tabs indicate missing values.

Brown_et_al_2024_impound_wc.csv - Impoundment water chemistry profiles and stratification information. Data for the Gunpowder River (GUNP) was obtained from the City of Baltimore, which owns and monitors Prettyboy Reservoir; site GUN0339 is at the gatehouse, affixed to ...