5 Conclusions
In the Potomac River Basin, the database, Water Balance Conveyance Model, and
interactive mapping tool described in this chapter may be used for a number of
purposes, and other basins may benefit from using a similar approach. Specifically,
the Water Balance Conveyance Model is easily adaptable to an endless array of
water use systems as well as spatial and temporal changes to those systems. This
model was developed to provide consumptive use estimates at the watershed scale
by representing transfers of water from withdrawal points to discharge points. The
model structure, which represents four types of sites (water withdrawal sites, water
treatment facilities, end users, and wastewater treatment facilities), is sufficiently
flexible to address the level of complexity of interactions and water transfers
present in the upper Potomac River Basin. But the water balance equations,
Eqs. (5), (6), and (8), for N ¼ 4 site types could be easily extended to a more
general model with N site types to represent other situations. Also, it is relatively
straightforward to add losses and return flows from conveyances to the equations if
the model were applied to regions with data to support representation of these types
of losses and returns.
The interactive mapping tool provides an easily understandable and readily
accessible way to make complex datasets available to diverse stakeholder interests.
Since these products are generated utilizing open-source software, the cost is
negligible and the system can be developed to accommodate local complexities.
Advances in technology that are available and usable by anyone are allowing water
resource agencies with limited budgets to undertake more sophisticated analyses for
use in decision-making and planning.
Select stakeholders may also utilize the tool to evaluate potential consequences
of changing water use. For example, when coupled with water availability data
(e.g., streamflows) from sources such as the Chesapeake Bay Program Watershed
Model and USGS’ StreamStats [48], the tool’s water use summaries may be utilized
to understand the water supply–water demand relationship. Similarly, the tool may
also be used to inform local, state, and basin-wide water resources planning efforts.
Challenges faced during the development of this tool are not unique to the
Potomac River Basin. They include (1) combining different water use datasets
into a common database format, (2) incorporating flexibility into the conveyance
model that is able to capture losses and returns to the system through various
processes, and (3) accommodating the considerable staff time and effort required
to obtain necessary programming skills to work with the open-source software
components.
The pilot version of the Water Balance Conveyance Model is implemented with
Microsoft Access for the Monocacy sub-basin. The next version will be
implemented in PostgreSQL, to interface with the interactive mapping tool. The
prototype mapping tool currently calculates consumptive water use using sample
withdrawal data and consumptive use coefficients, with the assumption of onsite
return flows. The next version of the mapping tool will make use of the withdrawal
166
J. Ducnuigeen et al.
In the Potomac River Basin, the database, Water Balance Conveyance Model, and
interactive mapping tool described in this chapter may be used for a number of
purposes, and other basins may benefit from using a similar approach. Specifically,
the Water Balance Conveyance Model is easily adaptable to an endless array of
water use systems as well as spatial and temporal changes to those systems. This
model was developed to provide consumptive use estimates at the watershed scale
by representing transfers of water from withdrawal points to discharge points. The
model structure, which represents four types of sites (water withdrawal sites, water
treatment facilities, end users, and wastewater treatment facilities), is sufficiently
flexible to address the level of complexity of interactions and water transfers
present in the upper Potomac River Basin. But the water balance equations,
Eqs. (5), (6), and (8), for N ¼ 4 site types could be easily extended to a more
general model with N site types to represent other situations. Also, it is relatively
straightforward to add losses and return flows from conveyances to the equations if
the model were applied to regions with data to support representation of these types
of losses and returns.
The interactive mapping tool provides an easily understandable and readily
accessible way to make complex datasets available to diverse stakeholder interests.
Since these products are generated utilizing open-source software, the cost is
negligible and the system can be developed to accommodate local complexities.
Advances in technology that are available and usable by anyone are allowing water
resource agencies with limited budgets to undertake more sophisticated analyses for
use in decision-making and planning.
Select stakeholders may also utilize the tool to evaluate potential consequences
of changing water use. For example, when coupled with water availability data
(e.g., streamflows) from sources such as the Chesapeake Bay Program Watershed
Model and USGS’ StreamStats [48], the tool’s water use summaries may be utilized
to understand the water supply–water demand relationship. Similarly, the tool may
also be used to inform local, state, and basin-wide water resources planning efforts.
Challenges faced during the development of this tool are not unique to the
Potomac River Basin. They include (1) combining different water use datasets
into a common database format, (2) incorporating flexibility into the conveyance
model that is able to capture losses and returns to the system through various
processes, and (3) accommodating the considerable staff time and effort required
to obtain necessary programming skills to work with the open-source software
components.
The pilot version of the Water Balance Conveyance Model is implemented with
Microsoft Access for the Monocacy sub-basin. The next version will be
implemented in PostgreSQL, to interface with the interactive mapping tool. The
prototype mapping tool currently calculates consumptive water use using sample
withdrawal data and consumptive use coefficients, with the assumption of onsite
return flows. The next version of the mapping tool will make use of the withdrawal
166
J. Ducnuigeen et al.