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Phillip J. Zarriello

Publications and source records attributed to Phillip J. Zarriello.

At least 19 recordsLinked to original sources
USGS2019

Methods for estimating regional coefficient of skewness for unregulated streams in New England, based on data through water year 2011

The magnitude of annual exceedance probability floods is greatly affected by the coefficient of skewness (skew) of the annual peak flows at a streamgage. Standard flood frequency methods recommend weighting the station skew with a regional skew to better represent regional and stable conditions. This study presents an updated analysis of a regional skew for New England developed using a robust Bayesian weighted and generalized least squares regression model. Nineteen explanatory variables for 153 streamgages were tested in the regression analysis, but none were statistically significant and, as a result, a constant model was selected to define the regional skew for New England. The constant model for the New England region has, in log units, a skew of 0.37, a model error variance of 0.13, and an average variance of prediction at a new site of 0.14. An assessment of the selected regional skew model was conducted using a Monte Carlo analysis. The Monte Carlo simulations reveal that the perceived pattern in the station skews among the 153 streamgages is an artifact of the sample variability and the covariance structure of the errors.

Connecticut, Maine, Massachusetts, New Hampshire, ↗
USGS2017

Magnitude of flood flows for selected annual exceedance probabilities for streams in Massachusetts

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Transportation, determined the magnitude of flood flows at selected annual exceedance prob­abilities (AEPs) at streamgages in Massachusetts and from these data developed equations for estimating flood flows at ungaged locations in the State. Flood magnitudes were deter­mined for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEPs at 220 streamgages, 125 of which are in Massachusetts and 95 are in the adjacent States of Connecticut, New Hamp­shire, New York, Rhode Island, and Vermont. AEP flood flows were computed for streamgages using the expected moments algorithm weighted with a recently computed regional skew­ness coefficient for New England. Regional regression equations were developed to estimate the magnitude of floods for selected AEP flows at ungaged sites from 199 selected streamgages and for 60 potential explanatory basin characteristics. AEP flows for 21 of the 125 streamgages in Massachusetts were not used in the final regional regression analysis, primarily because of regulation or redundancy. The final regression equations used general­ized least squares methods to account for streamgage record length and correlation. Drainage area, mean basin elevation, and basin storage explained 86 to 93 percent of the variance in flood magnitude from the 50- to 0.2-percent AEPs, respec­tively. The estimates of AEP flows at streamgages can be improved by using a weighted estimate that is based on the magnitude of the flood and associated uncertainty from the at-site analysis and the regional regression equations. Weighting procedures for estimating AEP flows at an ungaged site on a gaged stream also are provided that improve estimates of flood flows at the ungaged site when hydrologic characteristics do not abruptly change. Urbanization expressed as the percentage of imperviousness provided some explanatory power in the regional regression; however, it was not statistically significant at the 95-percent confidence level for any of the AEPs examined. The effect of urbanization on flood flows indicates a complex interaction with other basin characteristics. Another complicating factor is the assumption of stationarity, that is, the assumption that annual peak flows exhibit no significant trend over time. The results of the analysis show that stationarity does not prevail at all of the streamgages. About 27 percent of streamgages in Massachusetts and about 42 percent of streamgages in adjacent States with 20 or more years of systematic record used in the study show a significant positive trend at the 95-percent confidence level. The remaining streamgages had both positive and negative trends, but the trends were not statistically significant. Trends were shown to vary over time. In particular, during the past decade (2004–2013), peak flows were persistently above normal, which may give the impression of positive trends. Only continued monitoring will provide the information needed to determine whether recent increases in annual peak flows are a normal oscillation or a true trend. The analysis used 37 years of additional data obtained since the last comprehensive study of flood flows in Massa­chusetts. In addition, new methods for computing flood flows at streamgages and regionalization improved estimates of flood magnitudes at gaged and ungaged locations and better defined the uncertainty of the estimates of AEP floods.

Massachusetts↗
USGS2015

Groundwater and surface-water interaction and effects of pumping in a complex glacial-sediment aquifer, phase 2, east-central Massachusetts

The U.S. Geological Survey, in cooperation with the Town of Framingham, Massachusetts, has investigated the potential of proposed groundwater withdrawals at the Birch Road well site to affect nearby surface water bodies and wetlands, including Lake Cochituate, the Sudbury River, and the Great Meadows National Wildlife Refuge in east-central Massachusetts. In 2012, the U.S. Geological Survey developed a Phase 1 numerical groundwater model of a complex glacial-sediment aquifer to synthesize hydrogeologic information and simulate potential future pumping scenarios. The model was developed with MODFLOW-NWT, an updated version of a standard USGS numerical groundwater flow modeling program that improves solution of unconfined groundwater flow problems. The groundwater model and investigations of the aquifer improved understanding of groundwater–surface-water interaction and the effects of groundwater withdrawals on surface-water bodies and wetlands in the study area. The initial work also revealed a need for additional information and model refinements to better understand this complex aquifer system. In this second phase of the study, the original groundwater flow model was revised to improve representation of groundwater and surface-water hydrology, stabilize the model, and reduce model error. The model was simplified by reducing the number of layers from 5 to 3 and adding the MODFLOW lake package (LAK) to simulate Lake Cochituate and Pod Meadow Pond and better represent interaction between the lakes and the aquifer. Model revisions improved stability and shortened run times, allowing use of automated parameter estimation software (PEST) to further refine the model hydraulic parameters and reduce simulation errors. Model simulations indicate that under average base-flow conditions, the Birch Road wells have a small effect on flow in the Sudbury River during most months, even at the maximum pumping rate of 4.9 ft 3 /s (3.17 Mgal/d). Maximum percent streamflow depletion in the Sudbury River caused by simulated pumping takes place during simulated drought conditions, when streamflow decreased by as much as 21 percent under maximum continuous pumping. Simulations also indicate that groundwater withdrawals at the Birch Road site could be managed so that adverse streamflow impacts are substantially ameliorated. Under the most ecologically conservative simulated drought conditions, simulated streamflow depletion was reduced from 21 percent to 3 percent by pumping at the maximum rate for 6 months rather than for 12 months. Simulations that return 10 percent of the Birch Road well withdrawals to Pod Meadow Pond indicate a modest reduction in the Sudbury River streamflow depletion and provide a larger percentage increase to streamflow just downstream of the pond. The groundwater model also indicates that well locations can have a large effect on the sustainable pumping rate and so should be chosen carefully. The model provides a tool for evaluating alternative pumping rates and schedules not included in this analysis.

Massachusetts↗
USGS2014

Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management

Runoff-based indicators of terrestrial water availability are appropriate for humid regions, but have tended to limit our basic hydrologic understanding of drylands – the dry-subhumid, semiarid, and arid regions which presently cover nearly half of the global land surface. In response, we introduce an indicator framework that gives equal weight to humid and dryland regions, accounting fully for both vertical (precipitation + evapotranspiration) and horizontal (groundwater + surface-water) components of the hydrologic cycle in any given location – as well as fluxes into and out of landscape storage. We apply the framework to a diverse hydroclimatic region (the conterminous USA) using a distributed water-balance model consisting of 53 400 networked landscape hydrologic units. Our model simulations indicate that about 21% of the conterminous USA either generated no runoff or consumed runoff from upgradient sources on a mean-annual basis during the 20th century. Vertical fluxes exceeded horizontal fluxes across 76% of the conterminous area. Long-term-average total water availability (TWA) during the 20th century, defined here as the total influx to a landscape hydrologic unit from precipitation, groundwater, and surface water, varied spatially by about 400 000-fold, a range of variation ~100 times larger than that for mean-annual runoff across the same area. The framework includes but is not limited to classical, runoff-based approaches to water-resource assessment. It also incorporates and reinterprets the green- and blue-water perspective now gaining international acceptance. Implications of the new framework for several areas of contemporary hydrology are explored, and the data requirements of the approach are discussed in relation to the increasing availability of gridded global climate, land-surface, and hydrologic data sets.

Hydrology and Earth System Sciences↗
USGS2014

Simulated and observed 2010 flood-water elevations in selected river reaches in the Moshassuck and Woonasquatucket River Basins, Rhode Island

Heavy persistent rains from late February through March 2010 caused severe flooding and set, or nearly set, peaks of record for streamflows and water levels at many long-term U.S. Geological Survey streamgages in Rhode Island. In response to this flood, hydraulic models were updated for selected reaches covering about 33 river miles in Moshassuck and Woonasquatucket River Basins from the most recent approved Federal Emergency Management Agency flood insurance study (FIS) to simulate water-surface elevations (WSEs) from specified flows and boundary conditions. Reaches modeled include the main stem of the Moshassuck River and its main tributary, the West River, and three tributaries to the West River—Upper Canada Brook, Lincoln Downs Brook, and East Branch West River; and the main stem of the Woonasquatucket River. All the hydraulic models were updated to Hydrologic Engineering Center-River Analysis System (HEC-RAS) version 4.1.0 and incorporate new field-survey data at structures, high-resolution land-surface elevation data, and flood flows from a related study. The models were used to simulate steady-state WSEs at the 1- and 2-percent annual exceedance probability (AEP) flows, which is the estimated AEP of the 2010 flood in the Moshassuck River Basin and the Woonasquatucket River, respectively. The simulated WSEs were compared to the high-water mark (HWM) elevation data obtained in these basins in a related study following the March–April 2010 flood, which included 18 HWMs along the Moshassuck River and 45 HWMs along the Woonasquatucket River. Differences between the 2010 HWMs and the simulated 2- and 1-percent AEP WSEs from the FISs and the updated models developed in this study varied along the reach. Most differences could be attributed to the magnitude of the 2- and 1-percent AEP flows used in the FIS and updated model flows. Overall, the updated model and the FIS WSEs were not appreciably different when compared to the observed 2010 HWMs along the Woonasquatucket and Moshassuck Rivers.

Rhode Island↗
USGS2014

Simulated and observed 2010 floodwater elevations in selected river reaches in the Pawtuxet River Basin, Rhode Island

Heavy, persistent rains from late February through March 2010 caused severe flooding that set, or nearly set, peaks of record for streamflows and water levels at many long-term streamgages in Rhode Island. In response to this event, hydraulic models were updated for selected reaches covering about 56 river miles in the Pawtuxet River Basin to simulate water-surface elevations (WSEs) at specified flows and boundary conditions. Reaches modeled included the main stem of the Pawtuxet River, the North and South Branches of the Pawtuxet River, Pocasset River, Simmons Brook, Dry Brook, Meshanticut Brook, Furnace Hill Brook, Flat River, Quidneck Brook, and two unnamed tributaries referred to as South Branch Pawtuxet River Tributary A1 and Tributary A2. All the hydraulic models were updated to Hydrologic Engineering Center-River Analysis System (HEC-RAS) version 4.1.0 using steady-state simulations. Updates to the models included incorporation of new field-survey data at structures, high resolution land-surface elevation data, and updated flood flows from a related study. The models were assessed using high-water marks (HWMs) obtained in a related study following the March– April 2010 flood and the simulated water levels at the 0.2-percent annual exceedance probability (AEP), which is the estimated AEP of the 2010 flood in the basin. HWMs were obtained at 110 sites along the main stem of the Pawtuxet River, the North and South Branches of the Pawtuxet River, Pocasset River, Simmons Brook, Furnace Hill Brook, Flat River, and Quidneck Brook. Differences between the 2010 HWM elevations and the simulated 0.2-percent AEP WSEs from flood insurance studies (FISs) and the updated models developed in this study varied with most differences attributed to the magnitude of the 0.2-percent AEP flows. WSEs from the updated models generally are in closer agreement with the observed 2010 HWMs than with the FIS WSEs. The improved agreement of the updated simulated water elevations to observed 2010 HWMs provides a measure of the hydraulic model performance, which indicates the updated models better represent flooding at other AEPs than the existing FIS models.

Rhode Island↗
USGS2014

Simulated and observed 2010 floodwater elevations in the Pawcatuck and Wood Rivers, Rhode Island

Heavy, persistent rains from late February through March 2010 caused severe flooding that set, or nearly set, peaks of record for streamflows and water levels at many long-term U.S. Geological Survey streamgages in Rhode Island. In response to this flood, hydraulic models of Pawcatuck River (26.9 miles) and Wood River (11.6 miles) were updated from the most recent approved U.S. Department of Homeland Security-Federal Emergency Management Agency flood insurance study (FIS) to simulate water-surface elevations (WSEs) for specified flows and boundary conditions. The hydraulic models were updated to Hydrologic Engineering Center-River Analysis System (HEC-RAS) using steady-state simulations and incorporate new field-survey data at structures, high resolution land-surface elevation data, and updated flood flows from a related study. The models were used to simulate the 0.2-percent annual exceedance probability (AEP) flood, which is the AEP determined for the 2010 flood in the Pawcatuck and Wood Rivers. The simulated WSEs were compared to high-water mark (HWM) elevation data obtained in a related study following the March–April 2010 flood, which included 39 HWMs along the Pawcatuck River and 11 HWMs along the Wood River. The 2010 peak flow generally was larger than the 0.2-percent AEP flow, which, in part, resulted in the FIS and updated model WSEs to be lower than the 2010 HWMs. The 2010 HWMs for the Pawcatuck River averaged about 1.6 feet (ft) higher than the 0.2-percent AEP WSEs simulated in the updated model and 2.5 ft higher than the WSEs in the FIS. The 2010 HWMs for the Wood River averaged about 1.3 ft higher than the WSEs simulated in the updated model and 2.5 ft higher than the WSEs in the FIS. The improved agreement of the updated simulated water elevations to observed 2010 HWMs provides a measure of the hydraulic model performance, which indicates the updated models better represent flooding at other AEPs than the existing FIS models.

Rhode Island↗
USGS2014

Hydraulic assessment of existing and alternative stream crossings providing fish and wildlife passage at seven sites in Massachusetts

Seven existing road crossing structures at streams in Massachusetts were evaluated hydraulically and compared to hypothetical alternative structures designed for Aquatic Organism Passage (AOP) using standards developed by the Massachusetts River Continuity Partnership. Hydraulic simulations made for flood flows ranging from 20- to 0.2-percent annual exceedance probability (AEP) indicate that the existing structures are at full capacity for many of the simulated AEP floods, causing appreciable backwater upstream from the structure, which exacerbates upstream flooding and causes road overflow in many cases. The existing structures also create an impediment to AOP by failing to meet standards for openness, height, span, and velocity. Simulated hypothetical road crossing structures that provide for fish and wildlife passage by meeting or exceeding the AOP standards were able to convey most simulated AEP flood flows without causing appreciable backwater upstream from the structure. At sites where backwater was still present, it occurred only at the highest simulated flows and was compounded by the low downstream gradient that affected the water-surface elevation at the structure. The simulations of the alternative structures also indicate that, in addition to improved passage for fish and wildlife, the structures are more resilient to large floods and provide a greater buffer to uncertainties and potential changes in flood flows than the existing stream-crossing structures.

Massachusetts↗
USGS2013

Estimating irrigation water use in the humid eastern United States

Accurate accounting of irrigation water use is an important part of the U.S. Geological Survey National Water-Use Information Program and the WaterSMART initiative to help maintain sustainable water resources in the Nation. Irrigation water use in the humid eastern United States is not well characterized because of inadequate reporting and wide variability associated with climate, soils, crops, and farming practices. To better understand irrigation water use in the eastern United States, two types of predictive models were developed and compared by using metered irrigation water-use data for corn, cotton, peanut, and soybean crops in Georgia and turf farms in Rhode Island. Reliable metered irrigation data were limited to these areas. The first predictive model that was developed uses logistic regression to predict the occurrence of irrigation on the basis of antecedent climate conditions. Logistic regression equations were developed for corn, cotton, peanut, and soybean crops by using weekly irrigation water-use data from 36 metered sites in Georgia in 2009 and 2010 and turf farms in Rhode Island from 2000 to 2004. For the weeks when irrigation was predicted to take place, the irrigation water-use volume was estimated by multiplying the average metered irrigation application rate by the irrigated acreage for a given crop. The second predictive model that was developed is a crop-water-demand model that uses a daily soil water balance to estimate the water needs of a crop on a given day based on climate, soil, and plant properties. Crop-water-demand models were developed independently of reported irrigation water-use practices and relied on knowledge of plant properties that are available in the literature. Both modeling approaches require accurate accounting of irrigated area and crop type to estimate total irrigation water use. Water-use estimates from both modeling methods were compared to the metered irrigation data from Rhode Island and Georgia that were used to develop the models as well as two independent validation datasets from Georgia and Virginia that were not used in model development. Irrigation water-use estimates from the logistic regression method more closely matched mean reported irrigation rates than estimates from the crop-water-demand model when compared to the irrigation data used to develop the equations. The root mean squared errors (RMSEs) for the logistic regression estimates of mean annual irrigation ranged from 0.3 to 2.0 inches (in.) for the five crop types; RMSEs for the crop-water-demand models ranged from 1.4 to 3.9 in. However, when the models were applied and compared to the independent validation datasets from southwest Georgia from 2010, and from Virginia from 1999 to 2007, the crop-water-demand model estimates were as good as or better at predicting the mean irrigation volume than the logistic regression models for most crop types. RMSEs for logistic regression estimates of mean annual irrigation ranged from 1.0 to 7.0 in. for validation data from Georgia and from 1.8 to 4.9 in. for validation data from Virginia; RMSEs for crop-water-demand model estimates ranged from 2.1 to 5.8 in. for Georgia data and from 2.0 to 3.9 in. for Virginia data. In general, regression-based models performed better in areas that had quality daily or weekly irrigation data from which the regression equations were developed; however, the regression models were less reliable than the crop-water-demand models when applied outside the area for which they were developed. In most eastern coastal states that do not have quality irrigation data, the crop-water-demand model can be used more reliably. The development of predictive models of irrigation water use in this study was hindered by a lack of quality irrigation data. Many mid-Atlantic and New England states do not require irrigation water use to be reported. A survey of irrigation data from 14 eastern coastal states from Maine to Georgia indicated that, with the exception of the data in Georgia, irrigation data in the states that do require reporting commonly did not contain requisite ancillary information such as irrigated area or crop type, lacked precision, or were at an aggregated temporal scale making them unsuitable for use in the development of predictive models. Confidence in the reliability of either modeling method is affected by uncertainty in the reported data from which the models were developed or validated. Only through additional collection of quality data and further study can the accuracy and uncertainty of irrigation water-use estimates be improved in the humid eastern United States.

Eastern United States↗
USGS2012

Magnitude of flood flows for selected annual exceedance probabilities in Rhode Island through 2010

Heavy persistent rains from late February through March 2010 caused severe widespread flooding in Rhode Island that set or nearly set record flows and water levels at many long-term streamgages in the State. In response, the U.S. Geological Survey, in partnership with the Federal Emergency Management Agency, conducted a study to update estimates of flood magnitudes at streamgages and regional equations for estimating flood flows at ungaged locations. This report provides information needed for flood plain management, transportation infrastructure design, flood insurance studies, and other purposes that can help minimize future flood damages and risks. The magnitudes of floods were determined from the annual peak flows at 43 streamgages in Rhode Island (20 sites), Connecticut (14 sites), and Massachusetts (9 sites) using the standard Bulletin 17B log-Pearson type III method and a modification of this method called the expected moments algorithm (EMA) for 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probability (AEP) floods. Annual-peak flows were analyzed for the period of record through the 2010 water year; however, records were extended at 23 streamgages using the maintenance of variance extension (MOVE) procedure to best represent the longest period possible for determining the generalized skew and flood magnitudes. Generalized least square regression equations were developed from the flood quantiles computed at 41 streamgages (2 streamgages in Rhode Island with reported flood quantiles were not used in the regional regression because of regulation or redundancy) and their respective basin characteristics to estimate magnitude of floods at ungaged sites. Of 55 basin characteristics evaluated as potential explanatory variables, 3 were statistically significant—drainage area, stream density, and basin storage. The pseudo-coefficient of determination (pseudo- R2 ) indicates these three explanatory variables explain 95 to 96 percent of the variance in the flood magnitudes from 20- to 0.2-percent AEPs. Estimates of uncertainty of the at-site and regression flood magnitudes are provided and were combined with their respective estimated flood quantiles to improve estimates of flood flows at streamgages. This region has a long history of urban development, which is considered to have an important effect on flood flows. This study includes basins that have an impervious area ranging from 0.5 to 37 percent. Although imperviousness provided some explanatory power in the regression, it was not statistically significant at the 95-percent confidence level for any of the AEPs examined. Influence of urbanization on flood flows indicates a complex interaction with other characteristics that confounds a statistical explanation of its effects. Standard methods for calculating magnitude of floods for given AEP are based on the assumption of stationarity, that is, the annual peak flows exhibit no significant trend over time. A subset of 16 streamgages with 70 or more years of unregulated systematic record indicates all but 4 streamgages have a statistically significant positive trend at the 95-percent confidence level; three of these are statistically significant at about the 90-percent confidence level or above. If the trend continues linearly in time, the estimated magnitude of floods for any AEP, on average, will increase by 6, 13, and 21 percent in 10, 20, and 30 years' time, respectively. In 2010, new peaks of record were set at 18 of the 21 active streamgages in Rhode Island. The updated flood frequency analysis indicates the peaks at these streamgages ranged from 2- to 0.2-percent AEP. Many streamgages in the State peaked at a 0.5- and 0.2-percent AEP, except for streamgages in the Blackstone River Basin, which peaked from a 4- to 2-percent AEP.

Rhode Island↗
USGS2012

Simulation of groundwater and surface-water interaction and effects of pumping in a complex glacial-sediment aquifer, east central Massachusetts

The effects of groundwater pumping on surface-water features were evaluated by use of a numerical groundwater model developed for a complex glacial-sediment aquifer in northeastern Framingham, Massachusetts, and parts of surrounding towns. The aquifer is composed of sand, gravel, silt, and clay glacial-fill sediments up to 270 feet thick over an irregular fractured bedrock surface. Surface-water bodies, including Cochituate Brook, the Sudbury River, Lake Cochituate, Dudley Pond, and adjoining wetlands, are in hydraulic connection with the aquifer and can be affected by groundwater withdrawals. Groundwater and surface-water interaction was simulated with MODFLOW-NWT under current conditions and a variety of hypothetical pumping conditions. Simulations of hypothetical pumping at reactivated water supply wells indicate that captured groundwater would decrease baseflow to the Sudbury River and induce recharge from Lake Cochituate. Under constant (steady-state) pumping, induced groundwater recharge from Lake Cochituate was equal to about 32 percent of the simulated pumping rate, and flow downstream in the Sudbury River decreased at the same rate as pumping. However, surface water responded quickly to pumping stresses. When pumping was simulated for 1 month and then stopped, streamflow depletions decreased by about 80 percent within 2 months and by about 90 percent within about 4 months. The fast surface water response to groundwater pumping offers the potential to substantially reduce streamflow depletions during periods of low flow, which are of greatest concern to the ecological integrity of the river. Results indicate that streamflow depletion during September, typically the month of lowest flow, can be reduced by 29 percent by lowering the maximum pumping rates to near zero during September. Lowering pumping rates for 3 months (July through September) reduces streamflow depletion during September by 79 percent as compared to constant pumping. These results demonstrate that a seasonal or streamflow-based groundwater pumping schedule can reduce the effects of pumping during periods of low flow.

Massachusetts↗
USGS2011

Elevation of the March - April 2010 flood high water in selected river reaches in central and eastern Massachusetts

A series of widespread, large, low-pressure systems in southern New England in late February through late March 2010 resulted in record, or near record, rainfall and runoff. The total rainfall in the region during this period ranged from about 17 to 25 inches, which coupled with seasonal low evaporation, resulted in record or near record peak flows at 13 of 37 streamgages in central and eastern Massachusetts. The highest record peaks generally occurred in southeastern Massachusetts in late March - early April; at most other streamgages, the peak was in mid-March. Determination of the flood-peak high-water elevation is a critical part of the recovery operations and post-flood analysis for improving future flood-hazard maps and flood-management practices. High-water marks (HWMs) were identified by the U.S. Geological Survey (USGS) from April 13 through May 10, 2010, and by a consultant for Massachusetts Department of Conservation and Recreation (MADCR) after peak flows in mid-March and again in late March - early April. HWMs were identified at 25 river reaches in 7 designated Massachusetts Executive Office of Energy and Environmental Affairs (EEA) basins by the USGS and at 8 river reaches in 2 designated EEA basins by MADCR. The USGS identified 293 HWMs at 152 sites. A site may have more than one HWM, typically upstream and downstream from a bridge. The MADCR identified 133 HWMs; of these, 98 are at unique locations, and 29 of the 133 HWMs were visited once following the mid-March peak and again following the late March peak. The HWMs identified by the USGS and MADCR covered about 300 river miles, determined from the upstream and downstream HWMs (about 230 and 70 river miles, respectively). Elevation of HWMs was later determined to a standard vertical datum (NAVD 88) using the Global Navigation Satellite System and survey grade Global Positioning System (GPS) receivers along with standard optical surveying equipment.

Open-File Report↗
USGS2011

Elevation of the March-April 2010 flood high water in selected river reaches in Rhode Island

A series of widespread, large, low-pressure systems in southern New England in late February through late March 2010 resulted in record, or near record, rainfall and runoff. The total rainfall in the region during this period ranged from about 19 to 25 inches, which coupled with seasonal low evaporation, resulted in record or near record peak flows at 21 of 25 streamgages in Rhode Island and southeastern Massachusetts. The highest record peaks occurred in late March-early April and generally greatly exceeded the earlier March peaks that were near or exceeded the peak of record for 10 of the 25 streamgages. Determination of the flood-peak high-water elevation is a critical part of the recovery operations and post-flood analysis for improving future flood-hazard maps and flood-management practices. High-water marks (HWMs) were identified by the U.S. Geological Survey (USGS) from April 2-7, 2010, and by the U.S. Army Corps of Engineers (USACE) from April 3-7, 2010, in five major river basins including the Blackstone, Hunt, Moshassuck, Pawtuxet, and Woonasquatucket along the mainstems and in many tributaries. The USGS identified 276 HWMs at 137 sites. A site may have more than one HWM, typically upstream and downstream of a bridge. The USACE identified 144 HWMs at 127 sites. The HWMs identified by the USGS and USACE covered about 170 river miles, determined from the upstream and downstream HWMs. Elevation of HWMs were later determined to a standard vertical datum (NAVD 88) using the Global Navigation Satellite System and survey-grade Global Positioning System (GPS) receivers along with standard optical surveying equipment.

Open-File Report↗
USGS2010

Effects of water use and land use on streamflow and aquatic habitat in the Sudbury and Assabet River Basins, Massachusetts

Water withdrawals from surface-water reservoirs and groundwater have affected streamflow in the Sudbury and Assabet River Basins. These effects are particularly evident in the upper Sudbury River Basin, which prompted the need to improve the understanding of water resources and aquatic habitat in these basins. In 2004, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Conservation and Recreation, developed a precipitation-runoff model that uses Hydrologic Simulation Program-FORTRAN (HSPF) to evaluate the effects of water use and projected future water-use and land-use change on streamflow. As part of this study, the aquatic habitat in the basins and the effects of streamflow alteration also were evaluated. Chapter 1 of the report covers the development of the HSPF model that focuses on the upper Sudbury River Basin (106 square miles) but covers the entire Sudbury and Assabet River Basins (339 square miles). The model was calibrated to an 11-year period (1993-2003) using observed or estimated streamflow at four streamgages. The model was then used to simulate long-term (1960-2004) streamflows to evaluate the effects of average 1993-2003 water use and projected 2030 water-use and land-use change over long-term climatic conditions. Simulations indicate that the average 1993-2003 withdrawals most altered streamflow relative to no withdrawals in small headwater subbasins where the ratios of mean annual withdrawals to mean annual streamflow are the highest. The effects of withdrawals are also appreciable in other parts of the upper Sudbury River Basin as a result of the perpetuation of the effects of large withdrawals in upstream reaches or in subbasins that also have a high ratio of withdrawal to streamflow. The simulated effects of potential 2030 water-use and land-use change indicate small decreases in flows as a result of increased water demands, but these flow alterations were offset as a result of decreased evapotranspiration associated with the loss of deep-rooted vegetation. Simulations of reactivating production wells near the north end of Lake Cochituate indicate pumping could substantially affect lake levels and flows at the lake outlet or in nearby reaches in the Sudbury River during periods of low flow, but the effects vary depending on the source of the water to the wells, which is largely unknown. Chapter 2 of the report covers the fish-community assessment and comparison of streamflow-setting standards for protecting aquatic habitat. The fish-community assessment indicates the main stems of the Sudbury and Assabet Rivers are dominated by macrohabitat generalists. Water temperatures recorded in seven free-flowing reaches in the upper Sudbury River Basin at three sites unaffected by withdrawals or impoundments are generally suitable for cold-water fish; however, summer temperatures often rose to a level considered critical to long-term survival of brook trout. At four sites downstream from withdrawals or reservoirs, or both, summer water temperatures were often in the upper critical range for brook trout survival. Physically and statistically based methods for determining streamflows for protecting aquatic habitat were applied at 10 selected riffle sites in the Sudbury and Assabet River Basins. Physically based methods, R2Cross and Wetted-Perimeter, use site-specific physical and hydraulic information and a one-dimensional hydraulics model, HEC-RAS, to determine flows that meet the criteria set forth by the method. The median flow that meets 2-of-3 of the R2Cross hydraulic criteria (percentage of bankfull wetted perimeter, average velocity, and mean depth) ranged from about 0.07 to 0.72 cubic feet per second per square mile (ft3/s/mi2) with an overall median of about 0.24 ft3/s/mi2; the median Wetted-Perimeter target flow ranged from about 0.10 to 0.51 ft3/s/mi2 with an overall median of about 0.25 ft3/s/mi2. Statistically based methods?Tennant, New England Aquatic Base Flow (ABF)

Scientific Investigations Report↗
USGS2009

Effects of Water-Management Strategies on Water Resources in the Pawcatuck River Basin, Southwestern Rhode Island and Southeastern Connecticut

The Pawcatuck River Basin in southwestern Rhode Island and southeastern Connecticut is an important high-quality water resource for domestic and public supplies, irrigation, recreation, and the aquatic ecosystem. Concerns about the effects of water withdrawals on aquatic habitat in the basin have prompted local, State, and Federal agencies to explore water-management strategies that minimize the effects of withdrawals on the aquatic habitat. As part of this process, the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service and the Rhode Island Water Resources Board completed a study to assess the effects of current (2000-04) and potential water withdrawals on streamflows and groundwater levels using hydrologic simulation models developed for the basin. The major findings of the model simulations are: *Moving highly variable seasonal irrigation withdrawals from streams to groundwater wells away from streams reduces short-term fluctuations in streamflow and increases streamflow in the summer when flows are lowest. This occurs because of the inherent time lag between when water is withdrawn from the aquifer and when it affects streamflow. *A pumped well in the vicinity of small streams indicates that if withdrawals exceed available streamflow, groundwater levels drop substantially as a consequence of water lost from aquifer storage, which may reduce the time wetlands and vernal pools are saturated, affecting the animal and plant life that depend on these habitats. *The effects of pumping on water resources such as ponds, streams, and wetlands can be minimized by relocating pumping wells, implementing seasonal pumping schemes that utilize different wells and pumping rates, or both. *The effects of projected land-use change, mostly from forest to low- and medium density housing, indicate only minor changes in streamflow at the subbasin scale examined; however, at a local scale, high flows could increase, and low flows could decrease as a result of increased impervious area. In some instances, low flows could increase slightly as a result of decreased evapotranspiration from the loss of deeprooted vegetation (forest) associated with development. *In some subbasins where large areas of agricultural lands were converted to low- and medium-density housing, low flows increase because the consumptive domestic water use was projected to be less than consumptive agricultural water use. All agricultural water use was for irrigation purposes and was assumed to be lost from the basin through evapotranspiration.

Circular↗
USGS2009

Characteristics of the April 2007 Flood at 10 Streamflow-Gaging Stations in Massachusetts

A large 'nor'easter' storm on April 15-18, 2007, brought heavy rains to the southern New England region that, coupled with normal seasonal high flows and associated wet soil-moisture conditions, caused extensive flooding in many parts of Massachusetts and neighboring states. To characterize the magnitude of the April 2007 flood, a peak-flow frequency analysis was undertaken at 10 selected streamflow-gaging stations in Massachusetts to determine the magnitude of flood flows at 5-, 10-, 25-, 50-, 100-, 200-, and 500-year return intervals. The magnitude of flood flows at various return intervals were determined from the logarithms of the annual peaks fit to a Pearson Type III probability distribution. Analysis included augmenting the station record with longer-term records from one or more nearby stations to provide a common period of comparison that includes notable floods in 1936, 1938, and 1955. The April 2007 peak flow was among the highest recorded or estimated since 1936, often ranking between the 3d and 5th highest peak for that period. In general, the peak-flow frequency analysis indicates the April 2007 peak flow has an estimated return interval between 25 and 50 years; at stations in the northeastern and central areas of the state, the storm was less severe resulting in flows with return intervals of about 5 and 10 years, respectively. At Merrimack River at Lowell, the April 2007 peak flow approached a 100-year return interval that was computed from post-flood control records and the 1936 and 1938 peak flows adjusted for flood control. In general, the magnitude of flood flow for a given return interval computed from the streamflow-gaging station period-of-record was greater than those used to calculate flood profiles in various community flood-insurance studies. In addition, the magnitude of the updated flood flow and current (2008) stage-discharge relation at a given streamflow-gaging station often produced a flood stage that was considerably different than the flood stage indicated in the flood-insurance study flood profile at that station. Equations for estimating the flow magnitudes for 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods were developed from the relation of the magnitude of flood flows to drainage area calculated from the six streamflow-gaging stations with the longest unaltered record. These equations produced a more conservative estimate of flood flows (higher discharges) than the existing regional equations for estimating flood flows at ungaged rivers in Massachusetts. Large differences in the magnitude of flood flows for various return intervals determined in this study compared to results from existing regional equations and flood insurance studies indicate a need for updating regional analyses and equations for estimating the expected magnitude of flood flows in Massachusetts.

Scientific Investigations Report↗
USGS2004

Simulated effects of the 2003 permitted withdrawals and water-management alternatives on reservoir storage and firm yields of three surface-water supplies, Ipswich River Basin, Massachusetts

The Hydrologic Simulation ProgramFORTRAN (HSPF) model of the Ipswich River Basin previously developed by the U.S. Geological Survey was modified to evaluate the effects of the 2003 withdrawal permits and water-management alternatives on reservoir storage and yields of the Lynn, Peabody, and SalemBeverly water-supply systems. These systems obtain all or part of their water from the Ipswich River Basin. The HSPF model simulated the complex water budgets to the three supply systems, including effects of regulations that restrict withdrawals by the time of year, minimum streamflow thresholds, and the capacity of each system to pump water from the river. The 2003 permits restrict withdrawals from the Ipswich River between November 1 and May 31 to streamflows above a 1.0 cubic foot per second per square mile (ft3/s/mi2) threshold, to high flows between June 1 and October 31, and to a maximum annual volume. Yields and changes in reservoir storage over the 35-year simulation period (196195) were also evaluated for each system with a hypothetical low-capacity pump, alternative seasonal streamflow thresholds, and withdrawals that result in successive failures (depleted storage). The firm yields, the maximum yields that can be met during a severe drought, calculated for each water-supply system, under the 2003 permitted withdrawals, were 7.31 million gallons per day (Mgal/d) for the Lynn, 3.01 Mgal/d for the Peabody, and 7.98 Mgal/d for the SalemBeverly systems; these yields are 31, 49, and 21 percent less than their average 19982000 demands, respectively. The simulations with the same permit restrictions and a hypothetical low-capacity pump for each system resulted in slightly increased yields for the Lynn and SalemBeverly systems, but a slightly decreased yield for the Peabody system. Simulations to evaluate the effects of alternative streamflow thresholds on water supply indicated that firm yields were generally about twice as sensitive to decreases in the NovemberFebruary or MarchMay thresholds than to increases in these thresholds. Firm yields were also generally slightly less sensitive to changes in the NovemberFebruary than to changes in the MarchMay thresholds in the Peabody and SalemBeverly water-supply systems. Decreases in the JuneOctober streamflow threshold did not affect any of the system's firm yield. Simulations of withdrawal rates that resulted in successive near failures during the 196195 period indicated the tradeoff between increased yield and risks. The Lynn and Peabody systems were allowed to near failure up to six times. At the sixth near failure, yields of these systems increased to 10.18 and 4.43 Mgal/d, respectively; these rates increased the amount of water obtained from the Ipswich River Basin (relative to the firm-yield rate), as a percentage of average 19982000 demands, from 68 to 96 percent and from 51 to 75 percent, respectively. The SalemBeverly system was able to meet demands after the third near failure. Reservoir storage was depleted about 6 percent of the time at the withdrawal rate that caused the sixth near failure in the Lynn and Peabody system and about 3 percent of the time at the withdrawal rate that caused the third near failure in the SalemBeverly system. Supply systems are at greatest risk of failure from persistent droughts (lasting more than 1 year), but short-term droughts also present risks during the fall and winter when the supply systems are most vulnerable. Uncertainties in model performance, simplification of reservoir systems and their management, and the possibility of droughts of severity greater than simulated in this investigation underscore the fact that the firm yield calculated for each system cannot be considered a withdrawal rate that is absolutely fail-safe. Thus, the consequences of failure are an important consideration in the planning and management of these systems.

Scientific Investigations Report↗