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Tables for Water Quality for Healthy Corals (EPA Office of Water)

Table 1. Excerpt of results, adapted from the Exercise 1 worksheet on vulnerabilities to water quality threats in CNMI.

Parameter	Negative effect & mechanism	Drivers (sources/transport, pathways) of exposure	Changing exposures	Biological sensitivity	Biological adaptive capacity	Data & other resources	Notes
Nitrogen (N)	Spurs algal over-growth; blocks light/reduces coral symbiont photosynthesis; interferes with coral larval settlement/ recruitment; probably not directly toxic.	Primarily non-point sources: leaking septic systems, piggeries (common in American Samoa), contaminated ground water, and possibly unpaved roads. Point sources: wastewater treatment plants. Legacy N pollution from old pineapple farms. Where? (What are spatial patterns across islands?)	More intense rain events with larger pulses of N are projected, and also more drought (which makes soils more prone to runoff). A lot of off-grid development (residential), with possibly more undocumented exposures from changing development patterns, with potentially greater effects around coastal towns.	Need to find out how different species of corals vary in sensitively to algal overgrowth. Corals in assemblages exposed to repeated exposures tend to be more resistant that assemblages further away/on outer reefs. Community knowledge on this topic would be very valuable.	There may be better recovery for inner reefs with a history of exposures. Reef recovery may need assistance through management. If protected, corals that have been bleached but are not dead have recovery potential due to live tissue that can be re-colonized with symbionts.	CNMI-specific: WQ standards. General: EPA lit review; WQ threshold papers.	What species of algae are most favored by increased N? Sensitivity of corals to overgrowth may not vary much. Quite variable as to whether N is good or bad for corals; source/types of N matter in this regard, as do co-pollutants. From a standards perspective for toxicants, need to do a species sensitivity distribution, set a protective standard protecting, e.g., 95% of the species. Use stressor/responses gradients. Where is agricultural mainly? What is the distance from agricultural exposures to the reefs?

Table 2. Excerpt of results, adapted from the Exercise 2 worksheet on WQ interventions.

Intervention	Status of use/ effectiveness (past/ current/future)	WQ parameter(s) addressed, NPS/PS	How it works (mechanism)	Application considerations	Pros and cons (incl. reg use)	Notes
Reef restoration as coastal infrastructure	This was the topic of CNMI’s Draft Action Plan for Coral Reef Restoration, but it is unknown whether it has been implemented (need to check). For effectiveness info in general, see the USCRTF report on the value of coral reefs for coastal hazard risk reduction.	Sediments, nutrients, pathogens.	Put reef up as a barrier, reduces wave energy and protects the coast from impacts of storms, which helps reduce coastal erosion and therefore helps with nutrients, sediment sources.	Is there an organization that could take responsibility for long-term maintenance? There are geographic considerations, such as where most needed and/or where a reef would be sustainable (e.g., ocean currents appropriate). Takes a while for reefs to grow and become effective barriers. Have to consider the right coral species that are sufficiently robust. Can we find bleaching resistant corals?	Cons: expensive and hard to do at large scales. Only appropriate for voluntary (doesn’t lend itself to regulatory pathway). Pros: can be effective and tailored to where the problems are greater. Co-benefits include provision of a settlement structure for more corals (diversity), self-sustaining, providing habitat.	See the EPA’s “Action Plan for Restoration of Coral Reef Coastal Protection Services: Case Study Example and Workbook” for more on mechanisms and considerations. What is Dept of Defense presence at CNMI; they are doing a big effort on this, though mostly grey infrastructure. What entities are implementing/have a stake in various actions – e.g., ‘Reefense’, DARPA (Defense Advanced Research Projects Agency). Where would consideration of any needed active management come in?

Table 3. Excerpt of results, adapted from the Exercise 4 worksheet on strategic design of interventions.

Intervention (WQ parameters addressed)	Locations/ site types	How are env changes impacting the WQ parameter(s) (spatially, temporally)?	Impacts of env changes on intervention effectiveness thru direct physical damage	Potential design adjustments to maintain effectiveness	Trade- offs	Notes on questions, info gaps, resources
Post-construction soil stabilization with vegetation (for sedimentation, total suspended solids, turbidity, nutrients).	Construction sites, prioritized by steep gradients and other places vulnerable to erosion (depending on soil types).	Erosion increasing through time due to increasingly strong storms & hurricanes. A lot of construction falls in flood plains, which are potentially expanding due to climate change, with the likelihood of more flooding.	Severe storms could damage vegetation/plantings.	Select plants appropriate for soil type including water/flooding (or drought) tolerant species, depending on where the activity is. Consider timing of when plantings take place (e.g., not during storm season). See general EPA Action Plan for restoration of coastal protection services for more ideas.	Consider what invasive species occur in the area, because these are often encouraged by habitat disruption with construction. Seeding is cheap, but if shrubs/trees are needed, increases cost.	Consider budgeting for more ‘unexpected’ project failures due to climate impacts. Should there be changes in where some construction is allowed? Consider how backfilling lands affects the bigger picture of erosion/sedimentation; this could include increases in backfilling what used to be jurisdictional wetlands to create buildable lands. There may be implications for species that are selected for planting (e.g., tolerances to flooding/drought/erosion). Might consider combining with a runoff infiltration intervention that reduces the runoff volume that the vegetation has to deal with.