Initial thoughts on an Allocation Process for the Chesapeake Bay
1/8/02
What we are trying to achieve?
To recommend a process to the Water Quality steering committee to make allocations of
nutrients and sediments to each of the 9 major Bay Basins and 17 Basin- States. We suggest that
we will do this in 2 steps. That is, for now until the next steering committee meeting in late
January we will focus on the first step of allocating among the 9 major tributaries. Once we have
an idea of how the Steering committee would like to allocate among the 9 major tributaries we
would then work on a process for the states to use in allocating the tributary allocations among
the state jurisdictions.
Who are the players?
The water quality technical committee will be the lead in making recommendations to the
steering committee. The WQ technical committee will be supplemented with folks with needed
expertise like modeling or WQS criteria development.
What are the Issues?
Much of the allocation process deals with the need to achieve equity among the various sources
or in the case of the bay, among the various tributaries and jurisdictions. Perceived equity can be
an individualistic thing but probably the primary factors that we need to consider in our
allocation process include:
•	How do the water quality needs of the major tributaries relate to the water quality needs
of the Bay? If we achieve standards in the tribs how close are we to achieving standards
in the Bay? What is the effect of one trib on the other? on the Bay?
•	What water quality levels do we achieve for the various 'milestone' treatment scenarios?
What scenarios are most appropriate?
•	Should we?/How do we consider the loading increase pressures that result from growth in
the basin in establishing an allocation process? Is such growth spread in the basin or more
centered in 1 or 2 tribs?
•	How do we consider the controls already in place in the allocation process?
What is an appropriate allocation process?
As stated above , we will initially focus on an allocation process for the 9 major tributaries.
While there are many ways to allocate loadings, an approach we are recommending is generally
described below:
We will term the process of allocating the allowable loading to each of the 9 major basins as the
allocation cap process. We see the allocation cap process being separated into 3 major pieces for
reasons we will describe below:
-allocation cap of sediments
-allocation cap for nutrients for tribs south of the Potomac River

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-allocation cap of nutrients for tribs including the Potomac River and north
1) Proposed allocation cap process for sediments within the Bay
•	Sediments impacts are most likely localized in the tribs and less so in the Bay. Most
solids introduced into a tributary watershed stay within that watershed, settling out before
they can be transported to the Bay Therefore, if tributary caps are set that protects each
tributary then those caps should also protect the Bay
•	Based on the above, the allocation process for sediment for all 9 tributaries is fairly
straightforward. That is, the loading cap for sediments for each tributary will be set based
only on the needs of protecting water quality for sediments within that tributary. These
caps will also protect the Bay for sediment impacts.
•	Lewis will run some tracer model runs for sediments to verify that sediments only impart
a localized effect on the tribs and not the Bay. These model runs will be available for
presentation at the WQSC meeting in January. Previous model runs have convinced
Lewis and Rich that this localized effect is true.
2)	Proposed allocation cap process for nutrients for tributaries south of the Potomac River
•	As with sediments, preliminary model analysis indicates that tributaries south of the
Potomac River express their nutrient load impacts within the tributary itself and do not
impact other tributaries or the Bay. Therefore, like sediments, we will establish nutrient
loading caps based upon the needs of each of these tributaries.
•	Early tracer model studies support this contention but further tracer studies will be run,
after the WQSC meeting in January.
3)	Proposed allocation cap process for nutrients for tributaries including the Potomac River and
other tributaries north of the Potomac.
•	For these tributaries, there is influence of the nutrient load of these tributaries on other
tributaries in the Bay and on the Bay itself. So for these tributaries, the allocation process
is more complex and consequently there is a need for developing a process for identifying
appropriate loading caps among these northern tributaries.
•	For these tributaries, the allocation process will be iterative. That is, we will conduct
modeling analysis and based on the modeling results suggest appropriate further steps.
•	To start this allocation process, we will simply run some allocation runs as prescribed
below, and based on the results suggest further steps.
Developing an allocation cap for each tributary
Not to make this more complex than is needed, but the above simply breaks the allocation

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process for sediments and nutrients into discreet activities in an effort to simplify the process.
One is still left with the task of finding a process that will achieve an acceptable allocation (in
many cases, as described above, based only on the needs of the tributary). In its simplest terms
the allocation process could simply be to lower the allowable loading to a stream until water
quality standards are met. But to make this process more meaningful from a standpoint of
understanding of the controls that are needed to achieve the allocation cap and to try to make the
allocation caps equitable among tribs, we are recommending the following:
technology based approach
-	identify various levels of technology for point and non-point sources. The tributary
strategy workgroup is identifying about 4 levels of nutrient/sediment controls. These
scenarios start with a beginning level of effort that simulates what is the minimum
expected (I think the year 2000 progress run). The highest level of effort will be the 'e-
cubed' scenario (everything, everyone, everywhere). Two other level of effort scenarios
will be developed representing interim levels of effort between the above upper and lower
bounds. Proposed level of effort scenarios will be provided to the WQSC in the meeting
in January.
-For setting allocation caps for sediments for all tributaries and for nutrients for the
tributaries south of the Potomac River, the selected allocation cap load would be the load
from that level of effort scenario that is determined to be affordable and either meet water
quality criteria or provide the greatest water quality benefit.
-For setting allocation caps for nutrients for the Potomac River and Tributaries north,
assess the modeling results and determine next steps.
-Allocation caps will be established by making several modeling runs for increasing
sediment control levels as described above. These model runs will be conducted in the
first Q 2002, after the WQSC meeting in January.
-The first step in this process would be to identify that nutrient loading that would be
appropriate to achieve standards in the tributary itself, with no consideration for the
impact on the Bay. The process for identifying loading caps for sediments above would
be used in this part of the process. This cap load would define the 'upper bound' of the
final cap load for each tributary.
-	If the proposed water quality criteria for nutrients in a tributary were considered not
achievable (not affordable) then the resulting (affordable) load will be considered the
final cap load for nutrients for that tributary.
-If the tributary loading cap was sufficient to achieve water quality criteria within the
tributary, it would be further analyzed for further reductions along with other tributaries
whose 'upper bound' nutrient loading caps were also sufficient to achieve proposed
criteria. These 'achieving' tributaries would be further ratcheted down in loading until
either water quality criteria were met or the level of effort was considered not affordable.

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Remaining issues/ questions
1)	Will this approach be sufficient to give the states 'credit' for what controls they have installed
up to now?
2)	How will this approach address areas of the Bay watershed that have grown in the past? Will
grow in the future?
3)	When running the 'technology based' modeling scenarios, what land use/population year
should be used?

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