The Chesapeake Bay Total Maximum Daily Load, or “pollution diet,” is supposed to result in increased accountability in the effort to restore to the Bay.

What increased accountability exactly means has been up for grabs over the last few years. It was presumed the states would be made accountable by being given an absolute limit on the amount of nitrogen, phosphorus and sediment pollution they could send to the Bay as of 2025. But what the states were going to do with those new requirements was always an open question.

Since the imposition of the TMDL in 2010, Maryland and the other Chesapeake Bay partner states have all developed Watershed Implementation Plans expressly to answer the question, “How will you achieve the nutrient and sediment pollution requirements in your state?” As part of their guidance for writing these WIPs, the states were requested to describe their sub-allocation of load reductions by geographic area and source sector. This looks a lot like accountability rolling downhill.

Maryland’s TMDL agreement is mirrored in its WIP. Point sources of pollution are made accountable for almost all of their reducible load. (Reducible load is the difference between the loads that would result if nothing was done to try to reduce them and the loads that would result from doing everything technically feasible to reduce them. It is a hypothetical thing, and it is the basis of the TMDL pollution load allocation.)

Other pollution sources such as stormwater, septics and agriculture are made accountable for a smaller share of their reducible loads, either because the costs of reductions from those sources are very high or because imposing the reduction cost on the polluter is thought likely to create serious economic dislocation.

While decision makers have attempted to take into account the costs and practical prospects for achieving the pollution reductions that they are allocating, difficulties remain.

Maryland’s sub-allocation of load reductions leaves stormwater pollution sources with a $6.27 billion bill. But many of the counties and municipalities who are responsible for those stormwater sources are strapped for funds even before we start talking about this obligation.

It is not clear that the public that funds those counties and municipalities will be willing to bear those costs. And given the current budget realities of state and federal agencies, it does not seem likely that funding for those reductions can come from these sources.

Ultimately, responsibility for pollution should rest with those who generate it. (Yes, accountability does roll downhill to the polluter.) But in specifying how much load reduction each source is accountable for (or, conversely, how much pollution it is allowed to contribute), it is not necessary that those load reductions all actually come from that source. To see this, bear with a simple numeric example:

Assume a total load reduction requirement of 8x which is allocated among three sources. Source A is accountable for 1x; source B, is accountable for 3x, and source C, is accountable for 4x. If source A finds it much cheaper to buy 1x amount of reduction from source C (who must have additional reduction capacity) and does so, then the reduction requirement of 8x is still being met. Source A doesn’t reduce anything and now source C has to reduce 5x. If a lot of other conditions are met, allowing source A to buy its reduction allocation from source C does not change anything. Except in economic terms. In economic terms, the cost of achieving the desired outcome has been reduced.

As people cotton on to the fact that we are the polluters and we must bear the costs of reducing our pollution, the reasonableness of allowing, say, stormwater sources to get some of their pollution reduction allocation from other sources will become more apparent.

If all of the reductions required from stormwater sources must come by stormwater retrofits, and if this raises costs so high that voters come to question the whole process, it is not clear how we are better off. Nor would we be better off if the pressure to achieve impractical reductions from some particular source turned the accounting process into a sham.

Through its allocation of accountability for pollution loads, the TMDL has specified pollution reduction requirements only in a very general sense. But there remains the hazard that rigid regulation of this accountability will cause the process to come undone.

Flexibility in how the reduction obligations are met does not mean backing off the total load reductions that restoring the Bay demands. It just means allowing the polluters a way to do the job at the lowest cost feasible. And, because we are the polluters, why would we not want to do the job at the least cost?