lag time

What is Lag Time used for?

Lag time is important to measure for many different industries but here today we are going to discuss the lag time for water quality response for land treatment. There are some watershed land treatment projects over the past few years that have been reported and are not good enough to maintain the water quality after a good implementation of BMPs for the watershed.

Factors that are responsible for this failure are as high as the project itself. Such as—lack of landowner participation, climatic changes, bad selection of BMPs, mistakes in dealing with the pollution sources, low-level experimental design, insufficient level of treatment, etc. 

If you are keen to know more details about it, stay with us till the end. So, let’s dive into the details

What does the lag time mean? 

Lag time is the time march on between installation or maybe adoption of land treatment and an improvement of making water quality good. 

How is lag time calculated? 

Lag time is mostly expressed in minutes, and can be identified by diving the annular volume by the flow rate.

Lag Time in Water Quality Response to Land Treatment: 

 Today in this content, we will discuss every aspect that is responsible for lag time in water quality enhancement for land treatment. There are some major components which are involved that we have mentioned below: 

  1. Time Components: 

Time required for Installed or Adopted Practice to Produce effect: 

  •  Practices need to be installed in watersheds to give a huge range of effects, including lessening dissolved pollutant concentration or maybe the load. 
  •  Lessen the particulate pollutant concentration or maybe the load. 

National Nonpoint Source Monitoring Program: 

  • Upgrade the vegetative habitat  
  •  Upgrade the physical habitat  
  • Transform the desirable species 

The time needed to produce the above-mentioned effects will depend upon the degree of disfigurement and the practices selected, along with the nature of the effects themselves. 

  1. BMP Development: 

Once it is built, concrete and steel treatment works will begin to function, with a little lag time before the pollutant rate is lessened. Some other impotent source control measures may also take effect rapidly. For example, in the Lake Champlain Basin Watersheds (VT) NNPSMP Project (1993–2000), the implementation of livestock barring fencing over three months in the summer of 1997 resulted in notable nutrient concentration and load depletions and also depletion of grimy bacteria counts in two studies in the first post-treatment year (Meals 2001).  

  1. Source Behavior:  

The lag time between BMP implementation and depletion of pollutant losses at the field margins scale differs by pollutant kind and source. Erosion controls tend to have a rapid effect on the soil mislaying from a field (crop) such as cover crops, figure-out the farming. 

The time needed for Effect to Be conveyed to Water Resource: 

 Practice effects needed to be started at or near our practice location. However, usually, watershed managers and stakeholders always want these effects to pop up punctually in the water resource of interest during the watershed. The time needed to convey an effect on a water resource hang on several different factors, including: 

The path for conveying the effect is:  

  •  Directly in or adjoining to such as shade the water resource. 
  •  Overland drift such as particulate pollutants. 
  •  Overland and underground flow such as dissolved pollutants. 
  • Penetrate groundwater such as nitrate. 
  •  The path distances.  

 The path travel rate is as follows: 

  •  Fast such as trench and artificial drainage outlets to lakes, and oceans.  
  •  Moderate such as overland and hypodermic flow in porous land. 
  •  Slow such as groundwater penetration in absence of megaspores. 
  •  Very slow such as transport in a regional porewater. 

Precipitation path during the period of study: 

  •  Wet periods usually increase volume & transportation. 
  •  Dry periods usually decrease volume and transportation. 

Measurement Components:  

1. Trafficking with Lag Time: 

 In some situations, lag time is usually in between the land treatment & water standard is unavoidable. 

Although, it is impossible for anyone to foretell the exact time duration for lag, because in most cases, lag time usually goes beyond the length of the after-treatment monitoring duration, making it a problem to treat the water quality. 

So, how can we treat this hapless fact of life? Here are a few proposed outlooks. 

2. Identify the lag time& modify expectations: 

 When the water quality problem is identified then, all the private and public figures start expecting fast results. If your planning failed, then there would be frustration and reluctancy to pursing the plan to action. 

3. Distinguish the watershed: 

Before you start designing a land treatment system and a related monitoring program, some factors should be investigated such as the impact of lag time. 

Identifying the time of travel for aquifer movement is a plain example. Watershed characterization is a crucial step in the project planning process (USEPA 2005).  

4. Contemplate lag time during the selection & situating of BMPs: 

While designing any land treatment program, you should evaluate the potential BMPs whose practices might give you a fast improvement in water quality (for the watershed trait). 

What is a lag in a project? 

Lag is the aggregate time between the two tasks or sometimes, lag is the aggregate time by which a future activity may be a hold-up. 

 Lag is used in all four logical relations such  

  •  Finish-to-start (FS). 
  •  Start-to-start (SS). 
  •  Finish-to-finish (FS).  
  •  Start-to-finish (SF). 


It was a brief discussion about the lag time importance in the water quality response for eland treatment. Lag time for water quality sources is something that is adopted to improve the quality of water during land improvements. Sometimes, the expected results would not appear so, it’s become difficult to continue the process, or may be the managers of the project become somehow reluctant to continue the process because the risk of failure is increased in that case.

But we have shared a lot of factors that can be taken into the measure to avoid any failure in the future but yes, no one gives you an exact prediction for the best results. How did you find our content, let us know in the comment box below? 

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