DOI: 10.5061/dryad.d1240
title: Data from: A century of changing flows: forest management changed flow magnitudes and warming advanced the timing of flow in a southwestern US river

description: The continued provision of water from rivers in the southwestern United
 States to downstream cities, natural communities and species is at risk
 due to higher temperatures and drought conditions in recent decades.
 Snowpack and snowfall levels have declined, snowmelt and peak spring flows
 are arriving earlier, and summer flows have declined. Concurrent to
 climate change and variation, a century of fire suppression has resulted
 in dramatic changes to forest conditions, and yet, few studies have
 focused on determining the degree to which changing forests have altered
 flows. In this study, we evaluated changes in flow, climate, and forest
 conditions in the Salt River in central Arizona from 1914–2012 to compare
 and evaluate the effects of changing forest conditions and temperatures on
 flows. After using linear regression models to remove the influence of
 precipitation and temperature, we estimated that annual flows declined by
 8–29% from 1914–1963, coincident with a 2-fold increase in basal area, a
 2-3-fold increase in canopy cover, and at least a 10-fold increase in
 forest density within ponderosa pine forests. Streamflow volumes declined
 by 37–56% in summer and fall months during this period. Declines in
 climate-adjusted flows reversed at mid-century when spring and annual
 flows increased by 10–31% from 1964–2012, perhaps due to more winter
 rainfall. Additionally, peak spring flows occurred about 12 days earlier
 in this period than in the previous period, coincident with winter and
 spring temperatures that increased by 1–2°C. While uncertainties remain,
 this study adds to the knowledge gained in other regions that forest
 change has had effects on flow that were on par with climate variability
 and, in the case of mid-century declines, well before the influence of
 anthropogenic warming. Current large-scale forest restoration projects
 hold some promise of recovering seasonal flows.
description: Salt River Data
 SourcesList of data sources and
 data filesSaltRiverDataSources
 Apr2017.docxSalt River Historic and
 Current Forest ConditionsHistorical and current
 estimates of conditions of ponderosa pine forests in the Salt River
 watershed in central Arizona.SaltRiverHistoricCurrentForestConditions Apr 2017.xlsx1916-2012 Salt River Forest Water Use HistoryEstimates of historical forest management and human water demand within the Salt River watershed in central Arizona.1916_2012 SaltRiverForestWaterUseHistory Apr 2017.xlsx1914-2012 Salt River ClimateMonthly precipitation, temperature and potential evapotranspiration estimates from 1914-2012 for the Salt River watershed in central Arizona.1914_2012 SaltRiverClimate Apr 2017.xlsx1914-2012 Salt River StreamflowMonthly flows and trend estimates from 1914-2012 for the Salt River near Roosevelt in central Arizona.1914_2012 SaltRiverStreamflow Apr 2017.xlsx1914-2012 Salt River Magnitudes of Change in Flow ClimateEstimated magnitudes of change in monthly flows in Salt River near Roosevelt, Arizona from 1914-2012.1914_2012 SaltRiverChangeMagnitudesFlowClimate Apr 2017.xlsx1914-2012 Salt River Changes in Flow TimingChanges in timing of peak spring flows in Salt River near Roosevelt, Arizona.1914_2012 SaltRiverChangesFlowTiming Apr 2017.xlsx