Hydrology & Hydraulics
 The hydrology experience of Carr Research Laboratory, Inc. (CRL) includes diversified projects involving site inspections, field measurements, total problem solutions, public education, and applied research. The broad range of work transcends elementary stormwater and flooding studies. CRL takes an active role in education in the field of hydrology. The expertise and ability of CRL to solve the most difficult problems is recognized throughout Massachusetts and the northeastern United States.
Evaluation of FEMA Flood Profiles
On several projects CRL has independently evaluated the flood elevations generated for the Federal Emergency Management Agency (FEMA). We have succeeded in having FEMA revise their flood maps to match our evaluation of existing drainage basins.
Urban Hydrology
CRL has evaluated numerous sites for changes in peak flows due to urbanization. The quality of our work is excellent and this results in project approvals. Additionally, CRL’s work always satisfies the state’s reviewing agencies because our analyses are sound and include the most recent advances in hydrology. CRL now regularly integrates best management practices (BMPs) with urban flood control design.
Detention/Infiltration Basin Design
CRL has been called on to design detention basins when others have been unable to achieve required flood control and water quality management. We often design integrated stormwater management systems based on specific site conditions to achieve both flood control and stormwater quality management. Computer models developed by staff members allow us to design treatment systems accurately and efficiently. CRL has designed stormwater BMPs (see the related Stormwater BMPs page in this brochure) for more than 40 residential and commercial sites in the past 3 years. Most projects involve the integration of stormwater management, wetlands, floodplain, and riverfront issues.
A prime example of an integrated wetlands, rivers, and stormwater project is 2 Granite Avenue in Milton, MA. This site is specifically identified in the Rivers Protection Act. The project involved the replication of a salt marsh along the Neponset River, fish habitat enhancement, and management of stormwater runoff from a newly constructed office building and parking lot. The project was completed with a certificate of compliance at the end of 1997.
In another case, during subdivision design, CRL so carefully calibrated the detention basin shape and outlet structure that the basin size was significantly reduced. This gave great value to the client by (1) gaining a house lot, and (2) reducing excavation costs.
Hydrology of River Systems
Study of the hydrology of river systems includes evaluation of changes in flooding potential due to changes in storage, wetland character, and river geomorphology associated with a major river system. Some of CRL’s relevant river projects have evaluated development sites relative to Federal Emergency Management Agency (FEMA) flood maps and profiles. Some of our studies have resulted in revision to FEMA floodplains. CRL staff members have developed computer models to simulate river hydrodynamics for the Yellow River, the St. Lawrence River, and the upper Niagara River. See the related Rivers & Streams page for more information.
Applied Research
CRL has performed applied research on various aspects of urban hydrology. This includes rainfall statistics, evapotranspiration losses due to wetlands, and quantification of the base flow and storm flow components of mean annual runoff. This work also includes research on the number of rainfall events and their character as a function of time since the previous rainfall. The application of this work is for modeling nutrient budgets in lakes and ponds and for water resource planning.
Hydrology Chapters in Wetlands Book
Dr. Carr is the author of two draft chapters on hydrology for the Massachusetts Audubon Society’s publication "A Guide to Understanding and Administering the Massachusetts Wetlands Protection Act". This publications is widely used throughout Massachusetts for hydrologic evaluation of proposed projects that fall under the jurisdiction of the Wetlands Protection Act.
Urban Hydrology and Groundwater Hydrology Workshops
CRL has conducted several urban hydrology and groundwater hydrology workshops. The urban hydrology workshops run for ten evenings and review all the basic hydrology needed for evaluation of hydrologic changes due to urbanization. Lessons include evaluation of the rational method, use of the Modified Soil Cover Complex Method which is now required by MA environmental regulations, function of retention and detention basins, and inflow-outflow analyses. The groundwater hydrology workshops review basic applied groundwater hydrology and solutions of practical problems.
Micro-Computer Applications to Hydrology
Commercial computer programs are often useful when analyzing hydrological problems, however they are often limited in their capabilities. For this reason the CRL staff has developed several hydrologically related computer programs. These problems can only be developed with superior technical understanding of the subject matter. Our programs include a water budget model for lakes and reservoirs, a hydrograph calculation model using the Modified Soil Cover Complex Method, a flood routing program, and a pollutant removal rate program for detention basin design. A new groundwater mounding and infiltration program for recharge trench and large septic system design was recently developed.
Note that Dr. Carr is a Certified Professional Hydrologist American Institute of Hydrology (AIH), Certificate No. 481.
What are BMPs?
BMPs, or Best Management Practices, are engineering and non-engineering practices and techniques which mitigate the adverse impact on flooding and surface water quality resulting from land development and urbanization. Engineering practices include the construction of extended detention ponds, infiltration trenches, porous pavements, water quality inlets/outlets, grass swales, filter strips, pollutant/nutrient uptake wetlands, and erosion and sediment controls. Non-engineering practices include working with policies, regulations, construction and maintenance plans, and public education. Work often includes the review of stormwater management plans which ensure resource protection and ease of obtaining permitting.
HOW ARE COST AND MAINTENANCE EFFECTIVE BMPs DESIGNED?
Innovation and strong technical knowledge allow CRL to design suitable BMPs on a site-by-site basis. Each site has unique characteristics which will inherently affect the overall stormwater management goals. With years of experience and careful evaluation of each project on a site-by-site basis, CRL is able to design state-of-the-art, effective, BMPs in accordance with present local and state regulations.
HOW ARE POLLUTANT REMOVAL RATES CALCULATED?
For some projects, the new MA DEP Stormwater Management Standards require removal of at least 80% of the total suspended solids (TSS) in stormwater runoff. Based on EPA databases, CRL has developed computer programs to accurately calculate pollutant removal rates and determine structural dimensions for detention pond design.
HOW CAN SPACE BE CONSERVED WHILE STILL ACHIEVING PROPER FLOOD CONTROL?
Subsurface flood control can often save buildable land. CRL provides complete site services including on-site soil permeability testing, groundwater mounding calculations, and infiltration trench design. CRL has designed and reviewed dozens of infiltration systems to recharge and treat stormwater runoff. Most of the calculation techniques have been incorporated into our in-house computer programs which allows tasks to be completed in an efficient and orderly process.
WHY SHOULD YOU COUNT ON CRL?
The staff of CRL is constantly seeking new ways to improve our BMP designs and models. CRL subscribes to over 45 technological journals which focus on ecosystems and watershed protection. Dr. Wang is involved in peer review for some of these technical journals. Additionally, CRL was invited to speak at the MA Municipal Engineer's Association (1996) on "Performance Standards and Guidelines for Stormwater Management in MA."
What do our clients thinks?
"The members of Carr Research Laboratory designed an innovative restoration plan for sediment and erosion control. The plan prevented fine silt and clay from escaping our stormwater detention pond. This saved us thousands of dollars in DEP violations, fines, and pond expansion construction."
- Jon Graham, Hale Development |
