One of the specialized service areas Caltha provides is related to State and Federal water quality standards, environmental and aquatic toxicology, and setting site-specific water quality standards , water quality based effluent limits and NPDES permit limits. Caltha provides these services working directly for dischargers, or working with civil engineers needing to augment their team with specialized expertise in the areas of permitting and water quality standards.

Water Quality Standards Development
Our staff have prepared National Ambient Water Quality Criteria for US EPA in the past and today work with dischargers in many States to evaluate proposed and final State water quality standards. We have expertise in a wide range of chemicals, including metals, organic and inorganic industrial chemicals, pesticides and herbicides. We have also provided expert support in the assessment of nutrient criteria. On behalf of the regulated community, Caltha provides technical support in the development and evaluation of existing or proposed water quality standards and water quality benchmarks.
Expert Testimony, Public Comments and Technical Support For Legal Teams
Caltha can provide the expertise needed to evaluate and understand the impacts of local, State and Federal rulemaking and provide technical support to dischargers, engineering consultants, and legal consultants to prepare meaningful public comments. Caltha staff have provided expert testimony all levels, from local units of government to US EPA Science Advisory Panels. Caltha can augment your team with specialized expertise that is difficult to find elsewhere. Caltha routinely tracks rulemaking relating to water quality and wastewater discharge in States across the US which provides a headstart on benchmarking proposed rules and standards.
NPDES Permit Limits
We also work with dischargers and their engineers in developing site-specific water quality standards and negotiating water quality-based effluent limits (WQBEL). Caltha has provides expert technical support to plan and conduct studies and evaluations to develop site-specific permit limits and to conduct studies to quantify mitigating factors affecting toxicity of wastewater effluents. Caltha also provides a wide range of permit compliance support services, including development of pollution prevention plans, toxic organic management plans, spill plans & SPCC plans, and compliance training.
Antidegradation and Impaired Waters
Dischargers to some water bodies need to meet additional requirements, especially for new or expanded waste water discharges. These requirements are typically included in the State Antidegradation Policy. Caltha has the expertise to plan and conduct studies and evaluations to required to obtain State or Federal discharge permits for these special waters. Dischargers to listed “impaired waters” (303D listed waters) also may require further evaluations to demonstrate that do not cause or contribute to the impairment. For some types of discharges, the impaired waters status may restrict the ability to obtain an NPDES permit and can be critical in siting new facilities.
Aquatic Sediment Standards and Criteria
We have specialized experience assessing potential impacts of contaminated sediments, including sediment sampling, risk assessment and development of site-specific sediment cleanup goals.
Water Quality, Aquatic Toxicology and Biological Assessment
Caltha provides expertise in evaluating potential impacts of specific chemicals, preparing work plans and conducting field studies, including collecting water quality samples and collecting data and samples to characterize aquatic communities.


Caltha posts write-ups on selected projects on our web site. You can view an archive of past project summaries for this service area by clicking on one of the general project categories listed below:

>  Permitting

>  Water Quality