The harmful algal bloom will hit Lake Erie in late July. That contrasts with last year when the sickly green cover arrived at the beginning of June. The difference, according to the National Oceanic and Atmospheric Association? The lake temperature is cooler this year due to the higher-than-average rainfall.

On Thursday, NOAA and its research partners included that projection as part of their larger forecast for algae on the lake this summer. They are expecting a “significant” bloom in the western basin, measuring 7.5 on the severity index. Anything above 5 is viewed as having a “greater impact.” By comparison, the largest blooms in recent years occurred in 2011, at 10, and 2015, 10.5. Recall 2014, when the bloom exceeded 6 and infiltrated the Toledo water system, leaving 500,000 residents without drinking water.

So size doesn’t necessarily define toxicity. What matters is how the bloom takes shape, driven, in large part, by the winds. The blue-green algae that afflicts Lake Erie can generate the liver toxin microcystin, which poses a health risk to humans and wildlife. Yet even without the toxicity factor, the bloom is a problem, as the unsightly muck discourages tourism, recreation and related businesses.

Then there is the absence of sound stewardship, persistent algal blooms resulting in “dead zones" within the lake and otherwise diminishing the quality of what is a natural treasure, or what one generation is expected to preserve and protect for the next.

That is the significance of the NOAA forecast, the algal bloom further evidence of how we are failing to meet our generational obligation. If the forecast is correct, the lake will suffer the seventh significant bloom of the past decade. Go back to 2008, and it will be nine in 12 years. From 2002 to 2007, no algal bloom crossed the threshold of 5.

The condition of the lake is getting worse. Gov. Mike DeWine and others at the Statehouse understand as much. They know what is fueling the decline — phosphorous-ladened runoff from fertilizer, animal manure on farm land, septic tanks and partially treated sewage from cities. When heavy rains fall, as they have of late, more runoff flows into waterways and eventually the lake, though this year the rain has reduced planting, leaving less phosphorous in the runoff, the bloom not as severe as it might have been.

State lawmakers long have been circling the problem. A year ago, as he approached the end of his tenure as governor, John Kasich pressed for more aggressive action, identifying the primary contributor, agricultural operations in the Maumee River Valley. The Ohio Environmental Protection Agency finally designated as impaired the open waters of the western basin. Yet the necessary action, state or federal, has not followed, certainly nothing in line with the pledge of Ohio, Michigan and the Canadian province of Ontario — to reduce the phosphorous load 40 percent by 2025.

That is the evidence-based recommendation of scientists. It would help if state lawmakers backed the ambitious DeWine H2Ohio plan to dedicate $900 million during the next decade to improve water quality, addressing, for example, aging public works and the financial needs of farmers as they seek to reduce runoff. In that way, the federally funded Great Lakes Restoration Initiative is a boon to the effort. Yet the lesson from past environmental regulation is that clear markers and true accountability are required for success.

That means devising a plan to achieve the 40 percent reduction and setting up the enforcement mechanism to get there. No doubt, such steps will trigger resistance. Then, there’s the NOAA forecast about the harmful algal bloom and the mounting damage to Lake Erie. It reinforces the high stakes.