Human and environmental risk ranking of onsite sewage disposal systems for Oahu

This study evaluated the human health and environmental risk posed by on-site sewage disposal systems (OSDS). Oahu, Hawaii, was chosen as the study area for this project to develop and implement the methodology that will be applied to other islands in the future. The specific objectives of this study were to: • Estimate the quantity and types of OSDS on Oahu; • Estimate the effluent load discharged to the environment by these systems; • Identify which individual critical receptors (drinking water sources, streams and near shore waters) are most impacted by OSDS; • Identify other factors contributing to potential risk of OSDS; • Develop a risk scoring scheme based on various factors to assist regulatory managers in prioritizing inspection efforts for OSDS; and • Assign a risk score to each OSDS.Safe Drinking Water Branch, Department of Health, State of Hawai

Lahaina groundwater tracer study -- Lahaina, Maui, Hawaii

The studies presented in this report provide the positive establishment of hydrologic connections between the municipal wastewater injection from the LWRF and the nearshore region of the Kaanapali coast on the Island of Maui, Hawaii, and provide the results from the study’s principal objectives, which have been to: (1) implement a tracer dye study from the LWRF (Section 3), (2) conduct continuous monitoring for the emergence of the injected tracer dyes at the most probable points of emergence at nearshore sites within the coastal reaches of the LWRF (Section 2), (3) conduct an airborne infrared sea surface temperature mapping survey of coastal zone fronting the LWRF in an effort to detect cool and/or warm temperature anomalies that may be indicative of cool submarine groundwater discharge and warm wastewater effluent (Section 4), (4) complete radon and radium radiochemical surveys to detect the emergence points and flow rates of the naturally occurring submarine groundwater along the coastal zone (Section 5), (5) complete geochemical and stable isotopic analyses of LWRF effluent, upland well waters, terrestrial surface waters, marine waters, and submarine groundwater discharge in an effort to help partition the relative contribution of effluent waters to the ocean (Section 6), and (6) combine complete dye emergence breakthrough curves with which to develop groundwater models to determine the LWRFs effluent flow paths and rates of emergence to the coastal zone (Section 7).U.S. Environmental Protection AgencyDepartment of Health, State of HawaiiU.S. Army Engineer Research and Development Cente

Is it appropriate to apply porous media groundwater circulation models to karstic aquifers?

Written by renowned experts in the field, this book assesses the status of groundwater models and defines models and modeling needs in the 21st century. It reviews the state of the art in model development and application in regional groundwater management, unsaturated flow/multiphase flow and transport, island modeling, biological and virus transport, and fracture flow. Both deterministic and stochastic aspects of unsaturated flow and transport are covered. The book also introduces a unique assessment of models as analysis and management tools for groundwater resources. Topics covered include model vs. data uncertainty, accuracy of the dispersion/convection equation, protocols for model testing and validation, post-audit studies, and applying models to karst aquifers

Is it appropriate to apply porous media groundwater circulation models to karstic aquifers?

Written by renowned experts in the field, this book assesses the status of groundwater models and defines models and modeling needs in the 21st century. It reviews the state of the art in model development and application in regional groundwater management, unsaturated flow/multiphase flow and transport, island modeling, biological and virus transport, and fracture flow. Both deterministic and stochastic aspects of unsaturated flow and transport are covered. The book also introduces a unique assessment of models as analysis and management tools for groundwater resources. Topics covered include model vs. data uncertainty, accuracy of the dispersion/convection equation, protocols for model testing and validation, post-audit studies, and applying models to karst aquifers

WRRCTMR No.84 The Cell-Analytical-Numerical Technique for Solving Unsaturated-Flow and Solute-Transport Problems

The cell analytical-numerical (CAN) method was developed and applied for the solution of one dimensional water flow and solute transport problems in the unsaturated zone. The flow equation is characterized by a nonlinear governing equation. The CAN method is similar to other numerical techniques in that it divides the domain into a number of computational elements, each homogeneous in nature. It differs, however, by implementing a local analytical solution within the element. The soil moisture flux (for the flow equation) or solute mass flux (for the transport equation) is applied at the interface between two adjacent elements to define an algebraic relationship between the values of pressure head or concentration, respectively, at three neighboring points. Assembling these three-point equations provides a tridiagonal system of equations that can be solved by the Thomas algorithm. The system describing the flow problem is nonlinear in nature, and is solved iteratively within an implicit linearization scheme. For water flow, the method is applied to a number of soil types and the results are compared to Philip's semi-analytical solution and a numerical solution that is based on the finite-element technique. The results indicate the method's high accuracy over a wide range of soil types. However, an upstream weighting approach is needed for coarser soils, a process that may lead to relatively large mass-balance errors. The high accuracy of the solute transport solutions is demonstrated through comparison against available analytical solutions.U.S. Department of the Interior, Geological Survey Grant/Contract No. 14-08-0001-G1558-0

Decontamination of the Former Grayline Baseyard

Hawaii Department of Transportation, Airport Division; US Geological Survey (WRRIP grant no. 1434-HQ-96GR02666